Apache SpamAssassin is a mail filter that identifies spam. It is an intelligent email filter that uses a diverse range of tests to identify unsolicited bulk email, more commonly known as spam. These tests examine email headers and content to classify email with advanced statistical methods.
Login to your cPanel Account.
In the Email section, click the Spam Filters Icon.
Toggle Process New Emails and Mark them as Spam to enable it. If the knob/toggle is showing in grey color, it means the Apache SpamAssassin is disabled, and you need to enable it.
Now, whenever you receive a spam message with a spam score of 5 or more, the spam email will be automatically removed by Spam Assassin.