<b> creates bold text
</b> closes bold text
To create bold text, just sandwich the word(s) you want to appear in bold between the tags <b> and </b>.
For example, you might want to say something like:
<b>Help!</b> There's a <b>Webmonkey</b> in my house!
Which will look like this:
Help! There's a Webmonkey in my house!