E-faxing a document, without a fax machine

I have to sign a document, and fax it. The problem is I don't have a printer or fax machine handy, and won't for some time. I'm in the middle of nowhere. My question is, how can I electronically sign a document (even if that means just typing my name), and fax it to a fax number using a free e-faxing service online?

Thx

p.s.
I don't have a scanner either