Microsoft Word 97 established the word processing application as a market leader. During an unprecedented period of popularity in personal computers, Microsoft Word quickly found itself in almost all businesses and many homes, establishing itself as the de facto standard for creating written documents. As part of the Office 1997 software package, users were able to use the program to create simple documents and quickly became familiar with the toolbar and menu driven user interface which remained consistent through later releases up to 2003.
The DOC file extension has become so synonymous with word processed files that it is arguably the most widely known file extension. Used for files created by Microsoft Word for DOS through to Word 2003, the format has seen a huge number of improvements but was superseded with the release of Microsoft Word 2007. Many users of Word 2007 continue to use the old DOC format to ensure compatibility with other users from different businesses.
PDF is a file format developed by Adobe Systems for representing documents in a manner that is separate from the original operating system, application or hardware from where it was originally created. A PDF file can be any length, contain any number of fonts and images and is designed to enable the creation and transfer of printer-ready output.
Each PDF file encapsulates a complete description of a 2D document (and, with the advent of Acrobat 3D, embedded 3D documents) that includes the text, fonts, images and 2D vector graphics that compose the document. They do not encode information that is specific to the application software, hardware, or operating system used to create or view the document.