This process was invented before the Internet and seems laughably archaic at this point. To perform a fax, a person may type up a document, print it out, and scan it into the fax machine which sends it over the phone line. The person receiving the fax may then scan the faxed document and turn it back into a digital file. They’ve come full circle — the document was sent from one computer to another computer with much additional work and lost image quality.