When you compose a message, you should sign it. If it is business related, you may want to add additional contact information as well.
For example, your signature could read:
John Smith
Vice President of Engineering
Widgets Division
Acme Corporation, Inc.
303-555-1212 x111
john.smith@example.com
Rather than type this information every time, you can create your signature and enable the preference to include your signature to all your messages automatically.
Open Options and select the Mail Identity tab.
Select where the signature should be placed in your messages. Select Above included messages to add your signature at the end of the your composed, replied to, or forwarded text. Select Below included messages to add the signature at the end of the message.
If you want to always include the signature in your email messages, check Automatically add signature.
In the Signature text box, type the signature information exactly as you want it to appear in your messages.
Click Save.
The signature feature is available immediately. If you enabled to add your signature automatically, when you open a new compose window, your signature is added to the body of the message.