The Portable Document Format (PDF) is a universal container format for document exchange that contains all document parts and keeps the appearance unchanged. Thus, the page layout, typography, font or graphics are faithfully reproduced in PDF documents. In addition to text and graphics, audio, animation and video can also be included in PDF documents.
The PDF format was developed by Adobe from Postscript and extended with certain functionalities such as encryption and hyperlink. In 2008, the International Standards Organization( ISO) standardized the PDF file format under ISO Standard 32000-1. This makes the PDF format open and maintained and updated by ISO. PDF files can be viewed with an Acrobat reader. The file format can be generated in many graphics and pagination programs using a special print function. It is ideal for electronic publications, as well as for the creation of print products, distribution via the Internet and long-term archiving. The latter has also led to the PDF format being standardized in the PDF/A version - the "A" stands for archive - as ISO 19005 for long-term archiving.
For e-books there is a format called Mobile PDF. This format is a version in which the print version has been scaled down for e-book readers with 6" display, or similar size.