PDF is a file format that retains a document's true formatting across platforms and is useful for documents with complex formatting such as newsletters or financial statements. PDF files can be viewed and printed exactly as the author intended using a free PDF file reader.
Without a PDF file viewer, you will not be able to view or print PDF files. Your web browser may already have a PDF file viewer installed. If not, the following web sites describe how to download and install a PDF reader:
Browsers can handle many types of files. However, for some files such as movies, music, PDF files, etc., your browser needs Plugins or external applications that can handle those files.
If your browser doesn't have the needed Plugin or doesn't know what application to use to open the file, it can still save the file to your hard disk. When saving files, you can keep track of them using the Download Manager.
Plugins (a.k.a. add-ons) extend your browser's functionality and run inside the browser. You can find common Plugins by following the links shown, above.