---
title: "How to Fax From a Computer, and Receive One | PBXflex"
description: "Three ways to send a fax from a computer, how to receive one without a fax machine, and why fax machines fail on VoIP lines. Step by step."
url: "https://www.pbxflex.com/guides/fax-from-computer"
---

# How to fax from a computer, and receive faxes without a machine

By the PBXflex team. Updated October 17, 2026.

## The short answer

There are three ways to send a fax from a computer. An online fax service sends it from a web browser or app with no phone line: you upload the document, enter the fax number and send. A multifunction printer with fax sends it from the print dialog, over the printer's phone line. On Windows, Windows Fax and Scan sends it through a fax modem on a phone line. To receive faxes without a machine, you need a fax number that delivers each fax to an inbox as a document. Online fax does both, and it avoids the trouble fax machines have on internet phone lines.

## What you need to send a fax

Every fax has the same four parts, however you send it:

1. **The document**, as a file. A PDF is the safest choice. If the paper
   original is all you have, scan it or photograph it flat in good light.
2. **The recipient's fax number**, with the area code. In the US and Canada
   that is 10 digits.
3. **A cover sheet**, if the recipient expects one. It says who the fax is
   for, who sent it and how many pages follow. Our
   [fax cover sheet guide](https://www.pbxflex.com/guides/fax-cover-sheet) has free templates.
4. **A way to send it.** That is the choice below.

## Three ways to fax from a computer

| Method | What you need | Phone line | Receives faxes |
| --- | --- | --- | --- |
| Online fax | A web browser or app, and an online fax account | No | Yes, as documents in an inbox |
| Multifunction printer | A printer that supports fax, connected to your computer | Yes, plugged into the printer | Yes, on paper unless the printer saves them |
| Windows Fax and Scan | A Windows edition that includes it, and a fax modem | Yes, plugged into the modem | Yes, while the computer is on |

Online fax is the only one of the three that needs no phone line. It is also
the only one that needs no machine of your own, switched on and connected,
for faxes to arrive.

## Online fax, step by step

1. Sign in to your online fax service in a web browser or its app.
2. Start a new fax and enter the recipient's fax number.
3. Upload the document. Add a cover page if you need one.
4. Send it, and wait for the confirmation.

The service dials the recipient's machine and delivers the pages. Incoming
faxes work the other way round: the service answers your fax number and puts
each fax in an inbox as a document.

## A multifunction printer, from the print dialog

If your printer can fax, your computer can send a fax through it. On a Mac,
Apple's guide has you open the document and choose **File > Print**. Choose
your printer from the list under **Faxes**, type the fax number in
**Recipients**, and click **Fax**. You can add a cover page in the same
dialog. On Windows, the printer maker's software does the same job.

The printer still needs its own phone line. Faxes you receive usually print
on paper.

## Windows Fax and Scan

Windows Fax and Scan is included in some editions of Windows. To turn it on,
open **Control Panel > Programs and Features > Turn Windows features on or
off**, and tick **Windows Fax and Scan** under **Print and Document
Services**. If it is not in the list, your edition does not support it.
Microsoft says it is not available on Arm-based Windows PCs.

It sends and receives through a fax modem connected to a phone line, or
through a fax server on your network. It receives only while the computer is
on and connected.

## How to receive a fax without a fax machine

To receive faxes without a machine, you need a fax number that delivers to
an inbox instead of a printer. You have two ways to get one:

- **A new fax number** from an online fax service. Give it to the people who
  send you faxes.
- **Your existing number, moved.** If your fax number is printed on forms and
  letterhead, ask the online fax service to port it. Keep your old service
  running until the move is complete, so faxes keep arriving.

Once the number is in place, each fax arrives as a document. You can open
it, save it to a client or patient file, forward it, or print it if you need
paper.

## Fax machines on a VoIP phone line

Offices that move their phones to the internet often find the fax machine
stops working. A fax machine sends each page as a stream of modem tones, and
VoIP carries sound as packets of data that can garble those tones. A
standard called T.38 carries fax over the internet more reliably. It only
works when the fax equipment and the provider on each internet leg of the
call support it.

Online fax sidesteps the problem. It sends and receives documents, not
tones, so there is no machine on the line to fail.

## Getting a fax through the first time

- **Send a PDF.** It keeps the layout. Filled-in form fields can be lost when
  some tools flatten a file, so check the preview before you send.
- **Keep the file small.** Very large scans are slow, and some services limit
  upload size. A clear black-and-white scan at normal resolution is enough.
- **Dial the full number.** Include the area code, and check it against the
  recipient's letterhead or website.
- **Keep the confirmation.** It is your proof the fax was delivered, and when.

## How this works on PBXflex

PBXflex includes online fax on every plan, in the same app as your calls and
texts. A [fax extension](https://www.pbxflex.com/features/fax-extension) gives you a fax number and
a shared fax inbox, in the web app.

- **To send**, upload the document to the fax inbox and send it. Uploads can
  be up to 8 MB, and pages are sized automatically, so fewer are rejected by
  the receiving machine.
- **Every fax you send** produces a PDF delivery confirmation for the file.
  A failed fax retries automatically.
- **Filled PDF form fields and comments** survive the send, so nobody has to
  print and rescan a form.
- **Incoming faxes** arrive as documents in a shared inbox. When the sender
  is in your contacts, the fax shows their name. It is marked read once
  someone opens it.
- **Separate inboxes and folders** keep referrals, records and engagement
  letters apart.
- **A fax page uses 2 credits**, sent or received, from the same balance as
  your calls and texts.

Porting is free on every plan. The [switching guide](https://www.pbxflex.com/switching) explains
how moving a number works. If you want texting and fax but are keeping your
current phone system, see [Text & Fax](https://www.pbxflex.com/text-and-fax).

## Questions people ask

### Can I send a fax from my computer without a phone line?

Yes, with an online fax service. It sends the fax over the internet from a web browser or app, so the computer needs no modem and no phone line. A multifunction printer and Windows Fax and Scan both need a phone line.

### How do I receive a fax without a fax machine?

Get a fax number from an online fax service, or move your existing number to one. Each fax that arrives on that number lands in an inbox as a document you can open, save or print.

### Does Windows have built-in fax software?

Some editions of Windows include Windows Fax and Scan, which you turn on under Windows Features. It is not available on Arm-based Windows PCs. It sends through a fax modem connected to a phone line, or a fax server on your network.

### Can a Mac send a fax?

Yes, through a multifunction printer that supports fax. Apple's guide has you choose File, then Print, pick the printer under Faxes, enter the number and click Fax. Without such a printer, use an online fax service.

### Why does my fax machine fail on a VoIP line?

A fax machine sends each page as modem tones, and ordinary VoIP can garble them. A standard called T.38 carries fax over the internet more reliably, but only when every piece of equipment on the path supports it. Online fax avoids the problem, because it sends documents instead of tones.

### How do I know a fax went through?

Check the confirmation. A fax machine prints a transmission report. An online fax service shows a status, and on PBXflex every fax you send produces a PDF delivery confirmation you can keep with the file.

### What does it cost to send a fax on PBXflex?

A fax page uses 2 credits, sent or received, from the same balance as your calls and texts. One credit is one cent. Fax is included on every plan.

## Sources

- [Apple, Send a fax from your Mac using a multifunction printer (Mac User Guide)](https://support.apple.com/guide/mac-help/send-a-fax-mac-multifunction-printer-mchlp2449/mac)
- [Microsoft, Install the Windows Fax driver or service (turning on Windows Fax and Scan)](https://support.microsoft.com/en-us/word/install-the-windows-fax-driver-or-service-to-use-internet-fax-in-office)
- [Microsoft, Windows Arm-based PCs FAQ (Windows Fax and Scan availability)](https://support.microsoft.com/en-us/windows/experience/platform-variants/windows-arm-based-pcs-faq)
- [ITU-T Recommendation T.38, Procedures for real-time Group 3 facsimile communication over IP networks](https://www.itu.int/rec/T-REC-T.38)

## Keep reading

- [Online fax on PBXflex, with no machine or fax line](https://www.pbxflex.com/features/fax-extension)
- [Free fax cover sheet templates](https://www.pbxflex.com/guides/fax-cover-sheet)
- [IRS fax numbers, by form](https://www.pbxflex.com/guides/irs-fax-numbers)
- [Text & Fax, for teams keeping their current phones](https://www.pbxflex.com/text-and-fax)
- [Moving your numbers to PBXflex](https://www.pbxflex.com/switching)

## Contact

- Email: hello@pbxflex.com
- Phone: (877) 575 - 9527
- Address: 1001 Wilshire Blvd, Los Angeles, CA 90017
- Sign up: https://pbxflex.app/auth/sign-up