The Portable Document Format (PDF) is the file format created by Adobe Systems in 1993 for document exchange. PDF is a fixed-layout format used for representing two-dimensional documents in a manner independent of the application software, hardware, and operating system.[1] Each PDF file encapsulates a complete description of a 2-D document (and, with Acrobat 3-D, embedded 3-D documents) that includes the text, fonts, images, and 2-D vector graphics that compose the documents.

Just to add-
Most people use Adobe Acrobat Reader (available free at adobe.com) to open PDF files. You should be able to resize the contents to fit on the paper your printer uses, but probably won't be able to edit it in any other way.

It's best used for things like written materials (articles, instructions, even forms) that need to look the same no matter what computer or printer is used.

Wow, Letvia, I happen to be impressed!;)

And... it's a GREAT way to store scanned documents or screen shots. I save all my embroidery color changes in PDF files. :-) I believe the Windows' operating system has a built in PDF creator... if not, you'll have to buy Adobe Acrobat or another PDF creator. A PDF viewer is free however. See link. Good answer Letvia!

gillemmerson, I will just give you a *!

There you are, I could not answered that one any better. Actually no where near as good. *4U