How to Fax via the Internet: Complete Beginner Guide

By Alexey Spasskiy · Published April 3, 2026 · Updated June 8, 2026 · 9 min read

Quick Answer: To fax via the internet, open an online fax service (like mFax.to), upload your document, enter the recipient's fax number, and click Send. No machine, no phone line, and no trip to a print shop required.

Faxing via the internet works the same way as traditional faxing — but instead of a physical machine and a phone line, you use any device with an internet connection. The document travels as digital data, gets converted into a fax signal by the service's servers, and arrives at the recipient's fax machine or online fax inbox within seconds.

Whether you're sending a tax form to the IRS, submitting medical records, or signing a contract for a real estate deal, this guide walks you through every method, step by step. You don't need any technical background to follow it.

What Is Internet Faxing and How Does It Work?

Internet faxing (also called online faxing or e-faxing) lets you send and receive faxes over a broadband connection instead of an analog phone line. The result at the recipient's end is identical to a traditional fax — but you never touch a physical machine.

Here's what happens under the hood when you send an internet fax:

1. You upload your document to an online fax service and enter the recipient's fax number.
2. The service converts your file into a fax-compatible format (typically TIFF or PDF).
3. The converted document is transmitted to the service's fax gateway servers.
4. The gateway connects to the Public Switched Telephone Network (PSTN) and delivers the fax to the recipient's fax number — whether that's a physical fax machine or another online fax service.
5. You receive a delivery confirmation (timestamp + status) in your email or app.

The technical standard that makes this possible is called T.38 Fax over IP (FoIP). T.38 demodulates fax signals into IP packets, adds redundancy to handle packet loss, and re-modulates them at the receiving end — ensuring reliable delivery even over imperfect internet connections.

For a deeper dive, see our guide on how internet fax works.

Internet Fax vs. Traditional Fax

What You Need to Fax via the Internet

The requirements are minimal:

• A device — smartphone, tablet, laptop, or desktop computer
• An internet connection — Wi-Fi or mobile data both work
• Your document — PDF is best; most services also accept DOCX, JPG, PNG, and TIFF
• The recipient's fax number — a standard 10-digit fax number, with country code for international

That's it. No fax machine, no phone line, no printer.

3 Ways to Fax via the Internet

There are three main methods. Each suits a different situation — choose based on how often you fax and what devices you have.

Method 1: Mobile App (Fastest for Phone Users)

A dedicated fax app like mFax is the quickest option for smartphone users. You can snap a photo of a paper document, or upload a PDF from your camera roll or cloud storage, and send in under two minutes.

Best for: Anyone who faxes from their phone, occasional faxers, and people who need to fax signed paper documents.

Steps:

1. Download the mFax app (iOS or Android)
2. Open the app and tap Send Fax
3. Enter the recipient's fax number
4. Tap Add File — upload from your files, take a photo, or import from Google Drive / iCloud
5. Tap Send and wait for the delivery confirmation

Try mFax free — 5 million users, 4.8-star App Store rating.

Method 2: Web Browser (Works on Any Device)

Web-based fax services let you send a fax directly from your browser — no app download required. This is the best option on a work computer where you can't install software.

Best for: One-time faxes, computer users, anyone who doesn't want to install an app.

Steps:

1. Go to mfax.to in any web browser
2. Click Send a Fax
3. Enter the recipient's fax number (include country code for international)
4. Upload your document (PDF, DOCX, JPG, or PNG)
5. Add a cover page if needed, then click Send

You'll receive an email confirmation once the fax is delivered.

Method 3: Email to Fax

Most subscription fax services let you send faxes directly from your email client — no app, no website. You compose an email, attach your document, and address it to the recipient's fax number plus your provider's domain (for example, 15551234567@mfax.to).

Best for: Power users and businesses who want to fax without switching apps, and teams that want to integrate faxing into existing email workflows.

Steps:

1. Open your email client (Gmail, Outlook, Apple Mail — any)
2. In the To field, enter: [fax number]@[your-provider-domain]
3. Attach your document as a PDF
4. Add any message text in the body (it becomes the cover page)
5. Click Send — the fax is delivered automatically

Step-by-Step: Send Your First Internet Fax with mFax

Here's a complete walkthrough using mFax — the method works the same whether you're on the app or website.

How to Receive Faxes via the Internet

Receiving faxes online is just as straightforward as sending them — but it requires a virtual fax number (also called an online fax number or DID number).

A virtual fax number works exactly like a traditional fax number. Anyone can fax documents to it from a physical fax machine or another online fax service, and those faxes land in your email inbox or app as PDF attachments.

How to get a virtual fax number:

1. Subscribe to an online fax service (mFax Business starts at about $9/mo, billed annually)
2. Choose a local or toll-free number during sign-up
3. Share the number with anyone who needs to fax you
4. Incoming faxes arrive instantly as PDF attachments in your email or app

For businesses that handle high volumes or need compliance features, mFax Business provides dedicated virtual fax numbers, team inboxes, and HIPAA-ready infrastructure.

Internet Fax Costs: Free vs. Paid

The right pricing model depends on how often you fax.

Key cost drivers to watch:

• Overage fees — most plans charge $0.05–$0.15 per page over your monthly limit
• International faxes — typically cost 2–4× more per page than domestic faxes
• Receiving — some services charge extra for inbound faxes; mFax includes receiving in all plans

For free options without subscriptions, see our free internet fax comparison.

Is Internet Faxing Secure?

Yes — internet faxing is generally more secure than a physical fax machine sitting in an open office. Here's why:

Encryption in transit: Reputable services use TLS 1.2/1.3 encryption during transmission (the same standard that protects bank websites). Your document is never sent as plain text over the internet.

Encryption at rest: Once received, faxes are stored with AES-256 encryption — unreadable to anyone without the decryption key.

Access controls: Unlike a shared office fax machine where anyone walking past can read your documents, online fax delivers to your personal email or app inbox only.

Audit trails: Every send and receive event is logged with a timestamp, sender info, and delivery status — essential for HIPAA, legal, and financial compliance.

HIPAA compliance: If you're in healthcare, look for a provider that offers a signed Business Associate Agreement (BAA) — the legal contract required under HIPAA. mFax Business includes a BAA on all plans. For a full breakdown, see our guide to HIPAA-compliant fax services.

Internet Fax vs. Email: When to Use Each

A common question from beginners: if I can attach a document to an email, why would I use internet fax instead?

Use internet fax when:

• The recipient only has a fax number (not an email address) — this is still common in healthcare, legal, and government
• You need proof of delivery with a legal timestamp (email read receipts are unreliable; fax confirmations are not)
• You're sending documents that carry legal weight — contracts, court filings, IRS correspondence, insurance claims
• Compliance rules in your industry require fax (HIPAA, FINRA, certain state regulations)
• The recipient requires a signed document and you want to avoid DocuSign fees

Use email when:

• The recipient is happy to receive email attachments
• You don't need a legal proof-of-delivery record
• The document doesn't need to reach a physical fax machine

The two aren't mutually exclusive — many workflows fax the signed original and email a courtesy copy.

Common Troubleshooting Tips

Even internet fax isn't entirely problem-free. Here are the most common issues and their fixes:

Fax not delivered:

• Double-check the fax number — wrong numbers are the #1 cause of failed faxes
• Confirm the recipient's machine is on and has paper
• Try again later if you get a "busy" error; some machines don't have call-waiting

Document looks distorted on arrival:

• Convert to PDF before uploading (avoid Word or image files)
• Keep font sizes above 10pt — very small text can become illegible at fax resolution
• Avoid dark or colored backgrounds; fax machines print in black and white

Fax is taking too long:

• Multi-page faxes take 30–60 seconds per page on standard lines
• Large file sizes slow transmission; compress your PDF first with our free PDF optimizer

Receiving faxes but can't open the file:

• Check your email spam/junk folder — fax notification emails sometimes get filtered
• The attachment is usually a PDF or TIFF; open with any PDF viewer

Get Started

Faxing via the internet removes every friction point of traditional faxing — no machine to maintain, no phone line to pay for, no trip to a print shop. Any document you can open on your phone, you can fax in under two minutes.

Start with mFax — upload your document, enter the fax number, and send. Over 5 million users, 98% delivery success rate, 4.8 stars on the App Store.

For businesses that need virtual fax numbers, team inboxes, and HIPAA compliance, mFax Business lets you build your own plan — pick the exact seats and pages you need with a live calculator and pay only for what you use, from about $9/mo.