Does faxing only require scanned images or PDF?

I can't seem to figure out how to simply fax a text document (WorkCentre 3210). It seems my only choices are jpgs or scanned documents--therefore jpg/pdf. With the fax software including some 3d party ones I tried if I click on a text document or Docx, document the choice is greyed out. And if for ex. I go directly to Microsoft Word 2010 I also seem not to have that choice (I can send to email but not to fax). The same applies for my 2nd printer all-in-one (HP Officejet J4580)

So how does one fax a text document directly?