Although this is an ultra-beginner tutorial, it may be helpful to some nonetheless.

Bold Text example here
Code:
<b>Text Here</b>
Italic Text example here
Code:
<i>Text Here</i>
Underlined Text example here
Code:
<u>Text Here</u>
Strike-Through Text example here
Code:
<strike>Text Here</strike>
Over-Line Text example here
Code:
<span style="text-decoration: overline">Text Here</span>