Different attributes change message size.
In Outlook, you have three choices for e-mail message format: plain text, Rich Text Format (RTF), and HTML. The smallest type of message is a plain text message. As you add attributes to a message, that is, make it fancier by adding formatting or pictures, its size increases. Adding a large attachment will also increase a message’s size.
For more information about message formats, see the course Control how you send and see mail messages.
Tip By default, Outlook uses Microsoft Word as the e-mail editor. You can have Word remove extraneous HTML from your e-mail messages before you send them, making the messages smaller. Instructions for activating this feature are located on the Quick Reference Card at the end of this course.