There are a few different ways you can format your text in. Here are a few examples, plus the code you can use to do them:
<p><b>This text is bold</b></p>
This text is bold
<p><i>This text is italic</i></p>
This text is italic
<p>This is<sub> subscript</sub> and <sup>superscript</sup></p>
This is subscript and superscript
Here is a list of the different tags you use to format your text.
<b> – Bold text
<strong> – Important text
<i> – Italic text
<em> – Emphasized text
<mark> – Marked text
<small> – Small text
<del> – Deleted text
<ins> – Inserted text
<sub> – Subscript text
<sup> – Superscript text