There is great chance you already make a daily use of PDF files. PDF has been brought to you by Adobe, a major publishing software company. As PDF documents can be easily made, you can find them about everywhere : in the e-mail, on the Net, or on CD's. PDF is now a worldwide standard and you can send PDF documents to all your correspondents without risk. You can be pretty sure that, if they have a PC, they can read it. If this is still not the case, there will be no additional cost to them in order to do so. The only thing they need to browse and print those documents is the Acrobat reader that can be distributed free (on the Internet or CD).
Acrobat is available on Windows, Macintosh and Unix platforms.