If you are using your Plesk server for mail, you can set individual mailboxes to forward all mail they receive to external mailbox(es). To do this, follow the guide below.
1. To switch setup a forward on your mailbox, first login to Plesk, then go to Subscriptions - Click on the domain - then click on the Mail tab.
2. Click on the Mail tab, then the email address you are setting the forward on.
3. Click on the Forward tab, then tick the box which says 'Switch on Mail Forwarding'. Then specify the email addresses you'd like the mailbox email to be forwarded to - you can add multiple addresses - one address per line.
4. Click 'OK' to save the configuration and your forwarding will be active.