PDF is a worldwide standard for electronic documents. The standard was originally developed by Adobe® for the U.S. Federal Government to store legacy files. Now PDF files are used by government, regulated industries, financial services, lawyers, publishing industry, and education institutions. PDFfiles are used to distribute faxes, documentation, handbooks, court filing, letters, reports, and tax forms.

A PDF file preserves all the fonts, colors, and structure regardless of the software and hardware. Thus, the electronic copy of a PDF document is always identical to the original. The PDF document appears and prints identically to the original document.

PDF documents can be viewed on more than twenty hardware platforms, including Windows®, Linux®, Unix®, Mac®, Palm®, and Pocket PC, using freely distributed viewers like the Adobe Acrobat® Reader.

Moreover, the PDF format meets the legal documents requirements. This means that a PDF file cannot be altered without leaving an electronic footprint. In addition, PDF files provide document-level security, using 40-bit or 128-bit key, and they can be protected by the password. Content of the document can be protected from editing, copying, and printing as well.

Images, watermarks, hyperlinks, and annotations can be embedded into the PDF document. The ability to use tree-like structured bookmarks as outlines makes the navigation much easier.

PDF documents can contain interactive elements like input fields, list boxes, check boxes, and radio buttons. A PDF document is widely used because the PDF forms can be filled in, printed, or electronically submitted from a web browser and PDF files are compressed so they can be downloaded much faster and their storage takes much fewer resources.