A fax sending service lets you transmit documents online without a fax machine — from your phone, email, or browser. This guide explains how fax sending services work, what features matter, and which service fits your needs in 2026.
Frequently Asked Questions
What is a fax sending service?
A fax sending service is an online platform that lets you transmit documents to any fax machine or number over the internet — no physical fax machine required. You upload a file, enter a fax number, and the service converts and delivers it for you.
Is online faxing as secure as a traditional fax machine?
Modern fax sending services use 256-bit AES encryption, secure TLS transmission, and audit logs — features that traditional fax machines lack. HIPAA-compliant services like [mFax Business](https://mfax.to/business/) also provide a Business Associate Agreement (BAA), making them suitable for healthcare.
What file formats can I send with a fax sending service?
Most fax sending services accept PDF, DOCX, DOC, JPEG, PNG, and TIFF files. The service automatically converts your document into the TIFF format required by the fax protocol before sending.
How much does a fax sending service cost?
Pricing ranges from free (FaxZero, Fax.Plus 10-page free tier) to $4.99–$49.99/month for paid plans. mFax.to offers pay-per-fax pricing so you only pay when you actually send, making it ideal for occasional users.
Can I send a fax from my phone with an online fax service?
Yes. Most modern fax sending services offer a mobile app for iOS and Android. With the [mFax app](https://mfax.to), you can upload a PDF, snap a photo of a document, and send a fax in under 2 minutes directly from your smartphone.