iCloud: Automatically forward email in Mail on iCloud.com
You can have all your iCloud Mail messages forwarded automatically to another email account. You may find this helpful if you use several email accounts.
Automatically forward email
In Mail on iCloud.com, click the Action pop-up menu in the sidebar, then choose Preferences.
If you don’t see the sidebar, see Show or hide the sidebar in Mail on iCloud.com.
In the General pane, select “Forward my email to,” then type the forwarding address in the text field.
If you don’t want to store a copy of each forwarded message in iCloud, select “Delete messages after forwarding.”
Keep in mind that storing copies of forwarded messages decreases your available iCloud storage space.
You can also specify criteria so that only certain messages are forwarded. When you set up a rule to forward certain messages to another account, you can only use one forwarding address for each rule. See Set up rules to filter email in Mail on iCloud.com.