If you never want to receive messages from any address or domain again, you should add them to the blacklist. If you want messages sent from some address / domain to go directly to your inbox and not pass through a spam filter, you should add them to a whitelist.
To manage the above lists mentioned earlier, click on the "MailScanner" in cPanel.
Click the "Email Black / Whitelist settings" button.
Select the addresses you want to add on blacklist or whitelist.
1. Whitelist (does not pass through spam filter)
2. Blacklist (never want to receive messages from there)
3. Press the "Change" button to confirm your selection