A Message Signature is a way to automatically include a message in the footer of your e-mail, commonly used for including contact details and legal disclosures.
Your message signature can be created from the User Preferences page under the Settings menu. Once you have setup a signature it will be included in the message composer when sending e-mails.
You can toggle the inclusion of your message signature by pressing the Add/Remove Signature button under the message composer. You can also edit and remove it as you would with normal text in the composer if you wish.
