PDF, or Portable Document Format, is a file format for fixed-layout documents that include text in set fonts, and graphics. The primary purpose is to provide a format for printable documents which can be accessed independent of hardware, application software or operating system.
It is recommended that you use PDF only for documents that are intended to be printed. HTML is the preferred format for presentation of all other informational content on your website. If you must use PDF for some content, the document must be made accessible or the content must be provided in another, accessible format.