Select the text you want to underline.
In the Common
tab, click on the Underline 
button. You can also use the shortcut CTRL+U (Refer to list of shortcuts).
This option specifies the text that will be underlined.
Select the text you want to underline.
In the Common
tab, click on the Underline
button. You can also use the shortcut CTRL+U (Refer to list of shortcuts).
The selected text will be inserted between the tags <u> and </u>.