If you're also asking how to send a fax online (without a fax machine), you basically have 3 options:
Subscription-based online fax services — reliable, requires a subscription. examples are eFax, Fax Plus, Hello Fax
Physical places (FedEx, UPS) — works but costs per page and you have to go there in-person
One-time online fax — upload a PDF and send without setting anything up (no subscription).
For the one-time option, I use WhatTheFax.App -- the file gets deleted onces it's sent so you have total privacy. Also shows delivery status so you know it's sent (since IRS faxes sometimes fail if the line is busy).
Hope this helps.
