Hi,

Try following instruction:

1. Outlook 2010 and on File menu, click Options.
It will bring up Outlook Options dialog, from left sidebar select Mail and from main dialog window, click Stationary and Fonts.
2. Change font style & setting.
Apart from the basic settings,
3. You can also set some extra font settings such as; Font color, Underline Style and Color.
From Effects, enable different font effects options. You can see all the changes in Preview pane. Once done, click OK to continue.