| Introducing the Compose Page | Addressing Your Message | Writing Your Message | Personalizing Your Message | Attaching Files | Sending Your Message |
The Yahoo! Mail Compose page is where you write, address, and send email messages. You get to this page from the Mail tab.
Tip: If you want Yahoo! Mail to automatically add a signature to your outgoing emails, define the signature before your begin composing your first message—click here to learn how. Once your signature is set up, you’ll see it in the body of each new message you compose.
Open Yahoo! Mail. 
On the main Yahoo! Mail page, click the New button.

The Compose page opens.

Start composing an email message by addressing your message so Yahoo! Mail knows who to send it to.