Choose a Theme
Try It:
Select a Theme
Go to Tools->Options.
Go to Mail Format->Stationery.
Try the options:

What Do You See? When you return to the Mail
Format page, you should see the name of your Theme. The Theme
formats the Font sizes and color by default. However you can
select Always use my font and choose your own formatting if you
wish.
When you click on Font, you will be taken to the
same Font window that you've seen in Microsoft Word. Yes, and in fact,
the word processor in MS Outlook is Word.