By Sarah Martinez · Published February 8, 2025 · 12 min read
Quick Answer: Scan to email turns a paper page into a file (usually a PDF) and sends it as an email attachment. A copier or all-in-one printer does it with its Scan to Email button once its outgoing mail (SMTP) settings are filled in; a phone does it with its built-in scanner (Notes on iPhone, Google Drive on Android) and your mail app. If the office on the other end wants a fax, scan the page with mFax and send it to their fax number from the same phone.
A scanned page needs a way out of the machine, and email is the one everybody already has. Scan to email covers every route that ends with your document attached to a message: the button on an office copier, the scanner built into your phone's Notes or Drive app, or a flatbed scanner and a computer.
The routes look alike from the outside, but they break in different ways. Below is how each one works, the mail settings a printer or copier needs for Microsoft 365, Gmail and Outlook.com, what to check when scan to email stops working, and what to do when the form in your hand says fax, not email: snap it with the mFax app and fax it from your phone, free for 7 days.
What Is Scan to Email?
Scan to email is a feature of printers, copiers and scanning apps that saves a paper page as a file (PDF, JPEG or TIFF) and sends it as an email attachment. The page goes from the scanner glass to somebody's inbox without you saving or attaching anything by hand.
What happens behind the button matters the day it breaks. A scanner isn't a mail server: as Microsoft's setup guide puts it, devices like network scanners "create email messages, but are incapable of sending those messages without help." So the machine plays mail program:
- It scans the page and saves it as a file.
- It writes a message to the address you picked and attaches the file.
- It signs in to an outgoing mail server (SMTP) with the settings saved in it and hands the message over.
- The mail server delivers it like any other email.
Step 3 is the fragile one. The copier signs in with a password someone typed into it long ago, so when the mail provider changes its rules for devices, scan to email stops overnight while everything else in the office carries on.
Three Ways to Scan to Email
You can scan to email from a printer or copier, from your phone, or from a scanner connected to a computer. Pick by how often you scan and what is in front of you:
| Route | What you need | Best for | Setup |
|---|---|---|---|
| Printer or copier with a Scan to Email button | A multifunction printer with its email (SMTP) settings filled in | Offices that scan every day | Once, by whoever manages the printer |
| Phone camera, then your mail app | Notes or Files on iPhone and iPad, Google Drive on Android | A few pages, no scanner nearby | None |
| Scanner and computer, then attach | The Windows Scan app, or Image Capture on a Mac | A home flatbed or sheet-fed scanner | The scanner's driver |
How to Scan to Email from a Printer or Copier
On a printer or copier that is already set up, scanning to email takes five steps at the control panel. Menu names vary by brand (Scan, Send, Email, Scan to E-mail), but the order is the same:
Load the pages
Put a single page face down on the glass, or stack several pages in the document feeder. The feeder's label shows whether pages go face up or face down.
Choose Scan, then Email
On the control panel, tap Scan (or Send) and pick Email. Some machines first ask you to sign in or enter a PIN.
Pick the recipient
Type the address or choose it from the address book. Some offices limit the machine to address-book entries, so a new recipient may have to be added by whoever manages the printer.
Choose the file settings
PDF suits documents. Black-and-white or grayscale at the standard resolution keeps the file small; color and high resolutions make it much larger.
Start the scan
Press Start or Scan. The message arrives from the address the printer was set up with, which may not be yours, so check the spam folder if it doesn't show up.
Setting Up Scan to Email for the First Time
Scan to email is configured on the printer's built-in web page. Find the printer's IP address in its network menu (or print a network configuration page), type it into a browser on the same network, and open the scan or email settings. On HP business printers, HP's setup guide puts this under the Scan/Digital Send tab, where an E-mail Setup Wizard walks you through it. Whatever the brand, you fill in the same five things:
- SMTP server: the outgoing mail server, as a name like
smtp.office365.com, not an IP address. - Port and encryption: 587 with STARTTLS is the usual pair; 465 means encryption from the first byte (SSL/TLS); port 25 is often blocked by firewalls and internet providers.
- Sign-in: the mailbox address with its password or an app password, or a sign-in with Microsoft or Google (OAuth) on firmware that supports it.
- From address: what the recipient sees as the sender.
- Address book: saved recipients, so nobody has to type addresses on a touchscreen.
Send a test message to yourself before anyone relies on it.
SMTP Settings for Microsoft 365, Gmail and Outlook.com
These are the settings the big mail services publish for printers and scanners. Use the server names exactly as written:
| Mail account | SMTP server | Port and encryption | How the device signs in |
|---|---|---|---|
| Microsoft 365 (work or school) | smtp.office365.com | 587 (or 25), STARTTLS with TLS 1.2 or 1.3 | The sending mailbox's address and password, or OAuth. SMTP AUTH must be on for that mailbox; it is off by default in organizations created after January 2020 |
| Gmail (personal) | smtp.gmail.com | 465 (SSL) or 587 (TLS) | Your full address and a 16-digit app password; app passwords need 2-Step Verification on the account |
| Google Workspace | smtp.gmail.com, or the admin's relay smtp-relay.gmail.com | 465 or 587; the relay also takes 25 | OAuth (Google ended username-and-password sign-in for Workspace devices on May 1, 2025) or an app password where the account offers one. The relay recognizes the office by its IP address instead |
| Outlook.com / Hotmail | smtp-mail.outlook.com | 587, STARTTLS | Microsoft says Outlook.com requires modern authentication (OAuth2), so a printer that can only store a password may not be able to use it |
Sources: Microsoft's guide above, Google's guide for printers, scanners and apps, Google's app password help and Microsoft's Outlook.com settings page.
Two Microsoft 365 details trip people up. If a scanner recommends or defaults to port 465, Microsoft says it doesn't support the TLS versions Microsoft 365 requires, so it can't sign in this way at all. And Microsoft 365 rejects a scan whose From address differs from the mailbox that signed in, with 5.7.60 Client doesn't have permissions to send as this sender, unless that mailbox has Send As permission.
Scanning through Microsoft 365? Check it before January
Microsoft is retiring password sign-in (Basic authentication) for SMTP AUTH. Its current timeline: nothing changes until December 2026; at the end of December 2026 it is disabled by default for existing tenants, though an admin can still turn it back on; tenants created after that get it switched off by default; and the final removal date will be announced in the second half of 2027. A copier that signs in with a mailbox password needs a plan: firmware that supports OAuth, Microsoft's High Volume Email for scans that stay inside the organization, or an SMTP relay connector.
How to Scan to Email from Your Phone
Your phone already has a document scanner: Notes and Files on an iPhone or iPad, Google Drive on Android. It finds the page's edges and crops it, and the result goes out through your normal mail app, with no printer settings involved.
iPhone and iPad
- Open Notes, open or create a note, tap the Attachments button (the paperclip) and choose Scan Documents. In the Files app it's More (…) › Scan Documents.
- Hold the phone over the page. In Auto mode it captures by itself; otherwise tap the shutter, drag the corners to fit the page and tap Keep Scan. Add more pages, then tap Done.
- Open the scan, tap the Share button, choose Mail, add the address and send.
Apple's own steps are in its document scanning guide. Our guide to scanning and faxing from an iPhone adds tips for a clear scan, and they work just as well for email.
Android
- Open Google Drive and tap Camera in the lower-right corner.
- Aim at the page; a blue outline shows what will be kept. Take the photo, adjust it with Crop & Rotate, Filter or Clean, tap Add for more pages, then Done.
- Name the file, choose .pdf and tap Save.
- In Gmail, tap Compose, then Attach at the top right, choose Drive and pick the PDF.
The scanning steps are from Google's Drive help. An ordinary photo of the page works in a pinch, but scanner mode crops and flattens it; our guide to faxing a photo covers how to get a readable picture of a document.
How to Scan and Email a Document from a Computer
A scanner connected to a computer scans to a file, and you attach the file to an email yourself. That's one step more than a copier, and no mail settings to set up.
Windows
- Open the Windows Scan app (install it from the Microsoft Store if it isn't there).
- Choose your scanner, set Source to Flatbed, Feeder or Auto-configured, and pick a File type: JPEG, PNG, TIFF or Bitmap.
- Click Scan. The file is saved to Pictures › Scans unless you picked another folder.
- Attach it to a new message in Outlook, Gmail or any mail app.
The Windows Scan app saves images, not PDFs (Microsoft's steps). If the recipient asked for a PDF, run the image through our free document converter first. Windows Fax and Scan can scan too, on PCs that have it (it's missing on ARM-based Windows 11 PCs); our Windows Fax and Scan guide covers it.
Mac
With a scanner connected, open Image Capture, select the scanner in the sidebar and scan; with a document feeder it can put a multipage document into a single file. Then attach the file in Mail.
No scanner? Your iPhone can do it for the Mac. In a new Mail message, Control-click where the scan should go, choose Insert from iPhone or iPad, then Scan Documents. Scan on the phone, tap Keep Scan, then Save, and the scan lands in the email. Both devices need Wi-Fi and Bluetooth on and the same Apple Account (Apple's steps).
Scan to Email Not Working? Causes and Fixes
Most scan-to-email failures come down to the sign-in, the port, or the size of the file. The printer's error message, or the email log on the same web page where you set it up, tells you which:
| What you see | Likely cause | Fix |
|---|---|---|
| Authentication or login failed | The mailbox password changed; Gmail with 2-Step Verification won't take the normal password; SMTP AUTH is off for the Microsoft 365 mailbox, or the tenant's Security defaults block it | Create an app password (Gmail), have an admin enable SMTP AUTH for that mailbox, or move the device to OAuth or a relay |
| Can't connect, or a timeout | Wrong server name, or port 25 blocked by the network or internet provider | Use the provider's server name, not an IP address, and port 587 |
| TLS or SSL error | Firmware too old for TLS 1.2; port and encryption don't match (465 is SSL, 587 is STARTTLS); the printer's clock is far off | Update the firmware, match the port to the encryption, set the date and time |
| 5.7.60 Client doesn't have permissions to send as this sender | The From address isn't the Microsoft 365 mailbox that signed in | Make them the same, or give the mailbox Send As permission |
| Sent, but it never arrives | Spam filtering; Microsoft's Direct Send method can't deliver to outside addresses such as Gmail or Yahoo; the file was too big | Check the junk folder, send outside mail through authenticated submission or a relay, scan smaller |
| A "message too large" bounce | Over a mail service's size limit (next section) | Black-and-white, lower resolution, fewer pages per email |
If it worked for months and then stopped all at once, start with the first row. Mail providers tighten their rules for devices far more often than printers lose their settings.
How Big Can a Scanned Attachment Be?
Most mail services cap a message at 20–25 MB, counting everything attached to it. Business accounts go higher:
| Mail service | Size limit | Source |
|---|---|---|
| Gmail | 25 MB of attachments on personal accounts; Workspace admins set their own. Inside Gmail, a bigger file goes as a Drive link instead | |
| Yahoo Mail | 25 MB for all attachments in one message, incoming and outgoing | Yahoo |
| Outlook.com | 20 MB, counting the attachment and the email together | Microsoft |
| Microsoft 365 | 35 MB to send and 36 MB to receive by default; admins can set 1–150 MB | Microsoft |
Two catches. The smallest limit on the way wins: a scan within your own limit still bounces at a recipient whose limit is lower, and Yahoo's 25 MB applies to incoming mail too. And email inflates attachments in transit: Microsoft notes that messages leaving its datacenters grow by about a third in encoding, so a file that looks like it fits can still be refused.
To shrink a scan, rescan in black-and-white or grayscale at a standard resolution, split a long document across two emails, or compress the PDF with our free Optimize PDF tool. For anything bigger, a shared cloud link beats an attachment.
Is Scan to Email Secure?
Scan to email is fine for everyday paperwork and weak for anything sensitive. The scan leaves the copier encrypted only if TLS is on for that connection, and Microsoft lists TLS as optional for its relay and Direct Send methods. Copies of the file then sit in the inbox, in the Sent folder of any mailbox that keeps one, and anywhere it gets forwarded. A mistyped address sends the scan to a stranger.
Email can't prove anything arrived, either: no bounce is not a delivery. That's why many medical offices, insurers and agencies still take paperwork by fax, where the receiving machine confirms each page; our fax vs email comparison goes through the trade-offs. If you do email scans with personal details, lock the copier down the way PaperCut recommends: a sign-in at the device, encryption, and an audit trail of what was sent.
Scan to Fax: When They Want a Fax, Not an Email
Scan to fax is the same job with a fax number at the end instead of an email address. A fax-capable all-in-one does it over a phone line (see how to fax from a scanner); without a machine or a line, your phone becomes the scanner and mFax sends the fax. The camera scanner is in the mFax apps for iPhone, iPad and Android; on Windows or in a browser, you attach the PDF you already scanned, and one account works on all of them.
Start a new fax
Open the app, or start in your browser with your PDF, and choose New Fax.
Enter the fax number
Type the number with its country code: +1 for the US and Canada.
Scan or attach the pages
Snap the pages with the built-in scanner (edge detection and auto-crop turn them into a fax-ready PDF), or attach a PDF, Word file or image. Add a cover sheet if the recipient expects one.
Send it and keep the receipt
Check the page count and the estimated time, then press Send. The fax reads In Progress while the pages cross, about 40 seconds each, and Delivered once the receiving machine confirms every page. Download receipt gives you a PDF.
A single fax holds up to 60 pages and 100 MB, well past the 20–25 MB most inboxes accept. The longer walk-through, with scanning tips, is in scan to fax with your phone. Side by side:
| Scan to email | Scan to fax with mFax | |
|---|---|---|
| Arrives as | An attachment in an inbox | Pages on the recipient's fax machine, or in their fax inbox |
| Proof it arrived | None; you hear back only if it bounces | Delivered once their machine confirms every page, plus a PDF receipt |
| Size | 20–35 MB a message by default | Up to 60 pages and 100 MB a fax |
| What you need | Mail settings on the copier, or a mail app | The mFax app or a browser; no fax machine or phone line |
| Who asks for it | Anyone with an email address | Offices that take paperwork by fax: clinics, insurers, agencies |
Already Scanned It to Your Inbox?
Fax from your inbox with mFax Business. Every member of an mFax Business organization can send a fax by email: address the message to the fax number at send.mfax.to, digits only with the country code first (for example 12125550147@send.mfax.to), attach the scan and send, up to 60 pages and 20 MB a file. The address you sign in to mFax with is authorized automatically, and mail from any other address isn't faxed. So if the copier mails scans from a shared address such as scanner@yourpractice.com, attach the scan to a new message from your own mailbox; a forward carries the copier's text along, and the email body becomes the cover sheet's note. The subject becomes the cover sheet's subject; leave both blank and only the attachment is faxed. Keep patient details in the attachment, not the subject line. A status email comes back when the fax is delivered or fails. See mFax Business, from about $9/mo with a plan you build yourself, and our email-to-fax guide for the details.
Just need to send one scan as a fax? Open the mFax app instead: scan or upload the page and send it in under 2 minutes, free for 7 days.
Send Your Scan Where It Needs to Go
For an inbox, any route above will do: the copier's Scan to Email button once its SMTP settings are right, your phone's scanner and mail app, or a scanner and a computer. When the form says fax, get mFax on the App Store or Google Play, or open it in your browser, scan or upload the pages, and send them free with the 7-day trial. You'll see Delivered when the machine on the other end confirms every page.