You need a valid email address on the server and it's password to login to Plesk. Once you have the details please follow the steps below.
1. Go to plesk control panel and login with the following details.
Username : Your email address on the server, like [email protected]
Password : Password of email account.
2. Click Change Mail account Settings
3. Click Forwarding (Tab)
4. Select the Switch on mail forwarding checkbox.
Specify one or several email addresses to which email must be forwarded. When specifying email addresses, separate them with white spaces, commas, semicolons, or type each of them on a new line.
5. Click OK.