PDF files can be edited with Adobe Acrobat, a commercial program. The format can be opened and viewed using the free Adobe Reader or the Adobe Reader plug-in, which is available for most Web browsers. Search engines such as Google and Bing index PDF documents, so the Adobe Reader plug-in is commonly used when viewing search engine results. Some browsers, such as Google Chrome, provide native support for PDF viewing without the Adobe Reader plug-in. Also, Firefox can view PDF files with the PDF.js extension.
PDF files may contain text, images, forms, annotations, outlines, and other data. They preserve fonts and formatting electronically across multiple platforms and appear the same on the screen as they will when printed on paper.
View the PDF definition for more information.
NOTE: PDFs can be created in Mac OS X by selecting "Print..." from an application's File menu. Then instead of clicking "Print," choose "Save as PDF" from the PDF drop-down menu in the lower-left corner of the window.