You don't need a fax machine or phone line to send a fax. The best online fax services allow you to send and receive faxes via your email address, a mobile app, or a web portal—and sometimes for free.

Faxes are so 1980s. Who faxes anymore? Lots of folks, actually—from medical offices, small companies, and large corporations. And why? Well, let's say you want your doctor to send you a copy of your ...