Add a forwarding email to an existing email

You can't add forwarding to an actual email (these are addresses that have an email login and receive email, while forward and aliases only do not actually receive email and only forward messages on) using the website control this must be done through webmail

Go to your webmail (link is in the control panel under email tab below your list of mailboxes)

Click on the 3 horizontal bars on the top right of screen