About Portable Document Format
Portable Document Format (PDF) is a standard, universal file format used to display documents created from different applications or platforms. PDF documents offer the following advantages:
Using only a PDF Reader, you can view PDF documents without having to install the software used to create the original source files.
PDF format preserves the original layout of a source document and prevents changes from occurring during repagination when the PDF is opened on another computer. PDF files display with the same fonts and margin settings used in the original document.
A PDF file may contain additional information (bookmarks, hyperlinks, comments) to make its contents more accessible.
Bookmarks show the structure of a document. Click a bookmark to jump immediately to the required page. You can import bookmarks from Word documents or create them within Power PDF. You can also generate a Table of Contents automatically from bookmarks.
A Hyperlink is a special area that can be activated by a click. Hyperlinks give you quick access to another location in the same document or another document, or to a website page. Hyperlinks can also be used for special functions such as submitting a form.
Comments are written explanations or interpretation added to a document, and they can be identified by their authors based on color coding.
Additional controls are available, such as password protection, watermarks, compression settings and font embedding.
For details, see About PDF Versions.
About Tagged PDF files
Tagged PDF files contain metadata to describe the document structure and the order of different document elements such as pictures, text blocks, columns, titles, and more. The program can access this information and use it in addition to its own page layout detection while making editable files. Screen readers also use tag information to determine the best reading order for PDF contents. Not all PDF files are tagged.