Change the message format to plain text, HTML, or Rich Text

On the Tools menu, click Options, and then click the Mail Format tab.
In the Compose in this message format list, click the format you want.

From the main Microsoft Outlook window, on the Actions menu, point to New Mail Message Using, and then click the format you want to use.

Do one of the following:

Show When reading a Rich Text Format message

With the message open, on the Format menu, click the format you want to use (Plain Text or HTML).

Note If you use Word to read Rich Text e-mail messages, you cannot change the format of the message.

Show When reading a plain text or HTML message

With the message open, on the Edit menu, click Edit Message.
On the Format menu, click the format you want to use (Plain Text, HTML, or Rich Text).

Note If Word is not your e-mail editor, you can convert HTML or RTF to plain text, and you can convert plain text to RTF or HTML. However, you cannot convert HTML to RTF or RTF to HTML.

Show When composing a message with Word as your e-mail editor

With the message open, on the E-mail toolbar, click the format you want to use from the drop-down list (Plain Text, HTML, or Rich Text).

Show When composing a message if Word is not your e-mail editor

With the message open, on the Format menu, click the format you want to use (HTML, Rich Text or Plain Text).

Note If Word is not your e-mail editor, you can convert HTML or RTF to plain text, and you can convert plain text to RTF or HTML. However, you cannot convert HTML to RTF or RTF to HTML.

Open the contact card for the person.
In the E-mail box, double-click the contact's e-mail address.
In the Internet Format list, select the format you want to use for messages to this recipient.

Notes

You can only change the format for all messages sent to a contact with an SMTP e-mail address.
For information about plain text messages, see messages in plain text.