iCloud: Manage junk mail
Most junk mail (spam) sent to your @icloud.com address or its aliases are automatically identified and moved to your Junk mail folder when using Mail on iCloud.com. If you receive unwanted mail, you can mark it as junk. Messages marked as junk are displayed with a junk mail icon .
Important: Because messages in the Junk folder are automatically deleted after 30 days, periodically check the Junk folder for messages that were marked as junk mistakenly.
Mark a message as junk
Indicate that a message isn’t junk
Delete junk mail
By default, messages in the Junk folder are deleted after 30 days. To free up iCloud storage space before those 30 days, you can delete messages in the Junk folder at any time.
Do any of the following:
In the Junk folder, select the message or messages you want to delete, then click the Delete button in the toolbar.
If you don’t see the Delete button in the toolbar, click the Action pop-up menu in the sidebar, then choose Preferences. In the General pane, deselect “Show Archive icon in the toolbar.”
Drag the message to the Trash in the sidebar.
Select the message or messages you want to delete, then press the Delete or Backspace key.