TXT is a file format that contains the text, organized in rows. Text files opposed binaries that contain data that is not intended for interpretation as a text (encoded sound or image). The text file can contain both formatted and unformatted text. Since the very simple text files, they are frequently used for storing data.
RTF is a cross-platform format for storing labeled text documents, created jointly by Microsoft and Adobe, as meta-tags for the format Word in 1982. Adobe has in 1985 continued to develop the format and created a language PostScript. The basis is a simple text format, control sequences which are not macros that are available for change, and teams with a fixed behavior.