1. Log in as a user with your full username and password into your Smarter mail web mail "mail.yourdomainname.com"
2. Click on the "Option"(no. 1) icon at the top action panel to expand the drop down and select "Settings"(no. 2).
3. You will find the "Forwarding" option and fill in the "Forwarding Address" to complete the process.
Note :Make sure your forwarding email address is not the email accounts from free email services such as Gmail, Hotmail, Yahoo and etc. Kindly refer below link for our policy on forwarding.