You can include tables, colors, and so forth in your emails if you use HTML mode. To switch to this mode, simply click "Edit as Html" on the Compose screen. After a few seconds, you will see buttons appear for adding formatting to your email (as long as you are using a recent version of Internet Explorer, Netscape, or Firefox). If you always want to send email in this mode, click Options, then Account Preferences, and set Default compose mode to "HTML".
The 'Preview' button on the compose screen takes you to a screen where you can see the body of your message rendered in a browser window. This is useful if you have edited your HTML by hand. It can also be helpful if you just want to see what your message will look like using your current stylesheet.
The 'Preview' button is not visible when editing a message in Text mode; it is only displayed when you are editing an HTML message.
The 'Format' action automatically fixes up all kinds of formatting, for instance word wrapping and bullet list wrapping. If you have lines that you don't want to format, precede them with a '# '.