Access the SmarterMail web interface and log in using your email account credentials (not the domain admin account).
In the left-hand menu, navigate to:
Settings → Account
On the right-hand side, locate the Forwarding Address section.
In the Forwarding Address field, type the email address where you want to forward incoming messages.
Example: you@example.com
Click the Save button to apply mail forwarding.
Some versions may also allow you to keep a copy of forwarded messages in your inbox. If available, enable this option to retain copies of forwarded emails.