Plain text documents come in two flavors – rich text and plain text. Plain text, as you might have guessed, is rather plain. It supports standard ASCII characters, including numbers, symbols, and spaces, but does not support any type of text formatting. Therefore you cannot apply bold, italic, or underlined styles, and you cannot use different fonts or font sizes in a plain text document.
Because plain text does not contain information about text sizes or styles, it is the most efficient way to store text. Plain text documents often take up less than half the size of rich text documents containing the same number of characters. This is why log files, which contain a “log” of data generated by a program, are typically stored in a plain text format.
You can use a basic text editor such as Notepad or WordPad (for Windows) or TextEdit (for Mac) to create a plain text document. Other word processing programs can also create plain text documents, but you may have to use the “Save As…” command and choose the plain text option when saving the file. Keep in mind that if you change a rich text document to a plain text file, you will lose any formatting applied to the text.
Since converting rich text to plain text removes text formatting, this process can be used to strip all styles from formatted text. For example, if you use Windows, you can copy text from a formatted document and paste it into Notepad, which only supports plain text. If you copy the text you just pasted into Notepad, the unformatted text will be copied to your clipboard. The next time you paste the text, it will be pasted as plain text. If you use a Mac, you can do the same thing with TextEdit, but since the program supports rich text, you will need to select Format → Make Plain Text after pasting the text into the program.