![[Portable Document Format icon]](img/pdf.png "Icon for Portable Document Format files used on this site"){kind=small}
Portable Document Format, or PDF for short, is a type of document that will look the same on all computers and operating systems. The file contains all necessary information to make the document appear as the author intended it—all fonts and graphics are included and do not need to be downloaded separately. PDF files cannot normally be edited, however.
The most common program for opening PDF files is Adobe Reader, which is available for free for a large number of operating systems, including Microsoft Windows, Mac OS and various types of Unix.
Other programs that will open PDF files are Foxit Reader (for Windows and Linux), Ghostview (for Unix) or Preview (for Mac OS X, comes for free with any Mac).
In order to print out a PDF document, first open it in your PDF viewer, and then click on the File menu. Next, choose the Print option from that menu.
If your part of the world does not use A4-size paper, you may want to set your viewer to scale the document to fit the page. This will reduce it in size a bit, but makes sure everything will actually appear on the paper.