Type,

"< u >" (without the spaces) to begin an underlined section, and type,

"< / u >" (without the spaces) to end it.

The same goes for italics (the letter "i" instead).

The same goes for bold text (the letter "b" instead).

So, if I were to type,

"< u >< i >< b >text< / b >< / i >< / u >" (without the spaces), it would appear:

text