Sometimes you just need to provide a fake fax number to satisfy someone who insists on using this technology. The following information will teach you how to establish a fax number that comes through your email.
The usual advice
A fax to email service, such as that provided by eFax or MyFax will assign a fax number to you, where every fax message sent to that number gets automatically forwarded to your email as a PDF attachment.
It answers the requirement presented above, but comes with a caveat: these services are not free, and there isn't a pay-per-use fax service that provides fax-to-email for free. Some of these services offer free limited-time trials but that would require you to register an account and give away your personal details. Even worse, some require you to provide a credit card which they will start billing if you don't remember to cancel the subscription once you've received your fax.
We suggest a different approach, whose specifics depend on the question: do you actually need to see what's being sent to you? Or do you just need a fake number with a valid fax machine behind it?
If you need to see what's being sent to you
Check out the website called FaxToy. It's a fun project where anyone sending a fax to the following number will have that fax posted on the FaxToy website:
If you just need a fake number
Check out the dummy numbers we provide in our Dummy Fax Number article. Anyone dialing those numbers will get a response by a fax machine, and can send a fax message there. However, all faxes sent to those numbers just get deleted immediately.