How to Change Settings to Open a PDF File. A Portable Document File is a type of file that uses an open standard across different computer platforms and programs.

No matter your operating system, knowing how to combine PDF files is a good skill. We'll teach you the best ways to do so for Windows, macOS, or via the web.

How to Open a PDF File With Yahoo Mail. The Portable Document Format makes it possible for you to open and view documents, no matter what operating system, software or computer you have.