To send an email, click New in the toolbar or press c-N. The New Message form, shown in Figure 20-4, opens. Here's how you go about writing a message:
In the "To:" field, type the recipient's email address.
If somebody is in your Address Book (Section 20.6), type the first couple of letters of the name or email address; Mail automatically completes the address. (If the first guess is wrong, type another letter or two until Mail revises its guess.)