RTF means Rich Text Format
RTF is a file format developed by Microsoft and was intended to be used to exchange word processing files between different programs. Most people know the format of the WORDPAD application that is standard in Windows. Since the specification is free, anyone can make a program to read and write RTF files. Because of the advent of XML (also a way to exchange documents), RTF is not very popular and is still very much used. In RTF, the formatting codes begin with a backslash (), and you can use a brace ({) to indicate a grouping.