On some forums and message boards they allow what is called BBCode. It's the way that posters can include images and Gifs on the forum, yet it isn't HTML code. There are some links below that will show you how to accomplish various uses of BBCode for forums and message boards on the internet that uses that type of code.
This tip is how you can make underlined text and strikethrough text using BBCode. Just use these examples or substitute the example text with your own text.
Underlined Text:
