About Word Processing File Formats
A word processing file contains user information in plain text or rich text format. A plain text file format contains unformatted text and no font or page settings etc. can be applied. In contrast, a rich text file format allows formatting options such as setting fonts type, styles (bold, italic, underline, etc.), page margins, headings, bullets and numbers, and several other formatting features. The use of plain text files have reduced significantly with passage of time as there are more powerful computers and programs available to offer rich text files processing.
Common plain text file extensions and associated file formats include TXT, CSV, while file extensions for rich text documents include DOCX, DOC and RTF.