Anything you want. A fax or facsimile is nothing more than a copy of a document of any kind.
It could contain just about anything - a fax document is vey much like a letter - it just has a cover page on the front of it, and is sent over a phone line instead of through the mail.
a fax document is a document that has been sent over a fax machine.
open the photo file so that you can see the picture. Copy and paste the picture in the document or paste it in a document by itself. Then fax it like you would any other document from your computer.
A fax is a scanned document that is transmitted via a phone line to a receiving unit that prints the document.
A fax is a transmisison of an image of a document - whatever font the document was printed in will be transmitted by the fax. To change the font of the fax, reprint the document in a different font.
There is appears to be no meaning to the term "fax diffain". If the question is about "fax definition", then the definition of fax is a machine that scans a document, transmits it over a telephone line where it is received by a fax machine on the other end to print a facsimile (copy) of the document out.
Fax machine provide immediate copies of document.
A fax machine is suitable for sending a copy of a document.
You cannot fax a two-sided document. You must first take the two-sided document and make it two one-sided documents. Do this by selecting the 2 -> 1 feature on the printer/copier/fax machine's menu display and making a copy of the original document. You can then fax the two page document to the desired destination. But, as stated at the beginning of this answer, it is impossible to fax a two-sided document as a two-sided document. It must be a two page document (both pages being one-sided).
There are a number of ways: 1) Use a fax machine that can read two sided documents. For this is would need a document feeder that reads double sided pages. While most consumer level fax machines do not have this feature, most commercial ones will, as well as photocopiers / multifunction units that have a fax machine on them. 2) Copy the document from double sided to single sided - for this you'd likely need a photocopier or scanner to do the work. Once the document is single sided, you can now fax it.
WPAR
Fax is the document being sent through telephone lines of internet.