Plain text, Plain-text, or Plaintext is any text, text file, or document containing only text. Unlike a rich-text document, a plain text file cannot have bold text, fonts, larger font sizes, or any other special text formatting. The picture is a visual example of plain text vs. formatted text. Most associate plain text files with the file extension .txt on Microsoft Windows computers, however, can be any non-formatted file. To view a plaintext file, a text editor, such as Microsoft Notepad is used. However, all text editors including Microsoft WordPad and Word can also be used to view plaintext files because they have no special formatting.