Portable document format (PDF) files remain a popular choice for business documents ranging from contracts and forms to manuals and reports, so there's a good chance you need to open them often.

Q: Sometimes when I try to open a file or e-mail I get the message: "The selected file has an extension (PDF) that is not recognized by Windows Media Player but the player may be able to play it.

The Portable Document Format makes it possible for you to open and view documents, no matter what operating system, software or computer you have. To make this happen in Yahoo Mail, the email program ...

When it comes to preserving any type of document in a format that anyone can later open and be sure it looks right, it’s hard to beat the PDF format. PDF, or portable document format, was developed by ...