You can only do that if you send the body as HTML. And even then, the user may not see it the way you intended. Most email clients require that you click a link to see an email as HTML.

>In the following example the text called boody is used as the body of text in an outgoing email
>
>boody=boody+"The above shipment will be dispatched as soon as possible" +CHR(13) +CHR(13)
>boody=boody+"IN THE EVENT OF A NEED TO CANCEL THIS SHIPMENT PLEASE CALL TOTAL PARCEL NETWORK ON 01494 444008" +CHR(13)
>
>Using this method is it possible to change the size or color of the second of these lines?