Rich Text Format (RTF) is a file format that lets you exchange text files between different word processors in different operating systems. For example, you can create a file using Microsoft Word in Windows 98, save it as an RTF file (it will have a ".rtf" file name suffix), and send it to someone who uses WordPerfect 6.0 on Windows 3.1 and they will be able to open the file and read it. (In some cases, the RTF capability may be built into the word processor. In others, a separate reader or writer may be required.)
The RTF Specification uses the ANSI, PC-8, Macintosh, and IBM PC character sets. It defines control words and symbols that serve as "common denominator" formatting commands. When saving a file in the Rich Text Format, the file is processed by an RTF writer that converts the word processor's markup to the RTF language. When being read, the control words and symbols are processed by an RTF reader that converts the RTF language into formatting for the word processor that will display the document. The Specification, a copy of which is located in the archives at the World Wide Web Consortium, is used to create an RTF reader or writer.