Portable Document Format (PDF) is a widespread file format used for displaying documents created on different platforms or applications.
Advantages of this universal format are:
Software that created the original document does not have to be installed on the computer when opening a PDF. All you need is a PDF Reader.
PDF preserves the original layout of a source document. You can avoid changes during repagination of a document when it is opened on another computer. PDF files display with the same fonts and margin settings as the original.
A PDF file may contain additional information (bookmarks, hyperlinks, comments) to make its contents more accessible.
Bookmarks show the structure of a document. Clicking on a bookmark, you can jump immediately to the required page. Bookmarks can be imported from Word documents or created inside Power PDF. A Table of Contents can be generated automatically from Bookmarks.
A Hyperlink is a special area that can be activated by a click. Hyperlinks generally lead to another location either in the same document, or in another document, or they lead to a web address. Hyperlinks can also be used for special functions e.g. submitting a form.
Comments are written explanations or interpretation added to a document. Comments can be distinguished by their authors with different colors.
Further controls are available, such as password protection, watermarks, compression settings and font embedding.
See also: About PDF Versions.
About Tagged PDF files
Tagged PDF files contain metadata which describe the document structure and the order of the different document elements (e.g. pictures, text blocks, columns, titles). The program can access this information and use it in addition to its own page layout detection when making editable files. Screen readers also use tag information to decide the best reading order for PDF contents. Not all PDF files are tagged.