If you aren't using an enterprise spam filtering software, like our Spamexperts platform. Then you may receive a lot of spam emails.
One way you can reduce the amount of spam you receive on a cPanel server is to use SpamAssassin. SpamAssassin is inbuilt into cPanel.
To use it, simply log into the cPanel account you want to adjust the filtering on and choose the SpamAssassin Icon:
The default behaviour of SpamAssassin is to simply mark emails as spam by adding to the subject "***SPAM***" If you find it's missing emails that are spam, you can configure the filtering.
Here, you can put email addresses that you want filtered as spam. You can also use wildcard notation to block all subdomains. Such as *.tk or *.spamsite.com
Once you have the rules set up. You can also set SpamAssassin to automatically delete emails that exceed the spam score.