β© Automatically Forward Apple iCloud Messages
You can automatically forward all incoming iCloud Mail messages to another email address. This is useful if you want to send emails to another inbox or forward them to your Parsio Mailbox for processing.
Automatically forward all emails
Open Mail on iCloud.com and sign in to your account.
In the Mailboxes list, click the Settings button to open the Preferences pane.
Open the General tab.
Enable Forward my email to, then enter the forwarding email address.
(Optional) Select Delete messages after forwarding if you donβt want to keep a copy of forwarded emails in iCloud.
Keep in mind that storing copies of forwarded messages uses your available iCloud storage.Click Done to save your changes.
Forward only specific emails
If you only want to forward certain emails (recommended!), you can create a filter instead of forwarding all messages.
When creating the filter, choose to forward matching emails to your Parsio Mailbox.
Useful link
Official iCloud guide: Automatically forward emails