How to get a fax number for my printer depends on a fact about the printer: a multifunction printer faxes through a telephone line plugged into its rear, and the fax number is the number of that line, assigned by the phone company, not by the printer. If there is no line, the printer cannot fax and has no number. The alternative is an online fax number that a service answers and delivers to email, which needs no line and can be printed from the printer like any PDF. This page covers both routes, how to find the fax number on a printer that already has one, and how to set up a fax number without a line.
Where a printer's fax number comes from
Plug a phone line into the printer's line port and the printer faxes on that line's number. The number is in the phone company's records and on the phone bill; the printer's setup wizard asks you to type it in so it can print it in the header of outgoing pages, and that is the only place the printer stores it. A printer with no line connected has no number, however many fax buttons it has. So how to get a fax number for my printer, strictly, means ordering a phone line or using a line already in the building, and dedicating it to the printer or adding a switch that separates fax tones from voice calls.
How to find fax number on printer
Print the printer's configuration or fax settings report from its menu; the number it prints in the header is the one entered at setup. If the report shows no number or a wrong one, the header will be wrong on every fax you send, so correct it in the fax settings. If the printer is connected to a line and you do not know the line's number, dial out from a phone on that line to a mobile and read the caller ID, or check the phone bill. If the printer is on a business phone system, the extension is not a fax number; ask whoever runs the system which external number rings the printer's port.
How to set up a fax number without a phone line
Sign up to an online fax service; the plan includes a number the vendor answers from its data centre, and inbound faxes arrive as PDFs in an inbox or app, from which they can be printed on the same printer with no fax function used. Sending is done from a browser, an app or by email. At the vendors' printed entry prices that is Fax.Plus at $6.99 a month with 200 pages and one number included, CocoFax at $9.99, MetroFax at $11.95 with 550 pages, iFax at $12.49 and WestFax at $14.99 with 500 pages. The printer stays a printer, the phone line is never ordered, and the number can be ported to another service later because it is an ordinary number in the vendor's care.
Questions people ask about how to get a fax number for my printer
Can my printer fax over Wi-Fi without a phone line?
No. The printer's fax function uses a phone line. Over Wi-Fi it can print faxes received by an online service, which is the usual replacement.
Does the printer need its own line?
A shared voice line works with a fax-and-voice switch or by answering manually; a dedicated line is simpler. Neither is needed with an online number.
Can I keep the printer's old number on an online service?
Yes. Port the line's number into the online plan; WestFax prints a $20 one-time fee per number. The phone line can then be cancelled.