Change the default message format for all new messages
Specify
the default message format for one new message you'll create
Change the format of a message you received or
already created
With the message open, on the Format menu, click the format you want to use (Plain Text, HTML, or Rich Text).
Note If Microsoft Word is your e-mail editor, see Word Help.
Change the format for all messages sent to a particular contact
For Help on the format options, click the question mark ,
and then click the Internet Format box.