You can configure a header and a footer to appear in email messages that are generated from email templates that contain the $EMAIL_HEADER$ and the $EMAIL_FOOTER$ tokens.
From the navigation pane, go to Manage > Customization > Email templates.
The Email templates page appears.
In the upper right, click Email header and footer configuration.
The Email header and footer configuration page appears.
Enter text into the Header box and the Footer box.