HTML Text Formatting
Basic, or Plain Text, formatting is compatible with most E-mail programs, including Gmail (Google) and Hotmail (Microsoft). Plain text uses a default Font (Times New Roman!). By default, Office 365 uses HTML: the Text can be formatted big, bold and colorful.

1. Try it: Format with the Text
Go to Mail->Inbox->New Mail.
A new, untitled Message is open.
Enter the following text in the Message Box:
Plain Text cannot be formatted:
HTML can!

Select the text: HTML can!
Select a Font: Tahoma
Select a Font Size: 36
Select a Font Color: Blue

Enter your E-mail Address.
Enter the Subject: Plain Text or HTML

Click Send. An E-mail with rich Formatting should arrive in your Inbox.

Keep going...

Message->Format->Font