What is a plain text .TXT file?
A .TXT file is a bare bones format used to display text that can be read by 99.9% or all word processors. In its native format it can not display special formating like bold, italics, or underline but with a few tweaks of html you can include those features if your submission absolutely requires it.

What do you mean by tweaks?
Any file submitted to this site is screened for programming code, but will allow the following special formats to be utilized:
BOLD - To create a bold word simply surround it with the following tag convention - <b>text to be bold </b> will become text to be bold when displayed on screen.
ITALICS - To create a word in italics simply surround it with the following tag convention - <i>text to be italicized</i> will become text to be italicized when displayed on screen.
UNDERLINE - To create an underline under a word simply surround it with the following tag convention - <u> text to be underlined</u> will become text to be underlined when displayed on screen.

You will simply need to use these tags for any word that requires special formatting. (NOTE: Notice that you can use a single tag for multiple words. Put all words within the appropriate tag and it'll display in that format; just like the examples did above.)

How do I save in this magical universal format?
Saving as a TXT file is very simple. Follow the instructions below to "save as" a TXT file regardless of which word processor you use. (NOTE: 99.5% percent of all applications allow the following steps. You might have to adjust slightly depending on your program.)

Step 1: Open your file in your word processor.
Step 2: Go to the Command Menu across the top of your program.
Step 3: Choose SAVE AS (not save) from the menu under File.
Step 4: Use the SAVE AS TYPE Drop Down list (click the tiny arrow) and select Plain Text Format.
Step 5: The filename changes to the .txt file extension. Click Save.