If there is an IP address or domain which you want to block from your website, then you can block that IP address or domain using cPanel you can do it by following below steps:
Step 1. Login to your cPanel account and then select "IP Blocker" under "Security" section.
Step 2. Enter IP address or domain which you want to be blocked under "Add an IP or Range".
Step 3. Click on the "Add" button.
If you wish to unblock an IP address or domain then you can do it from the same feature "IP Blocker" scroll down to the currently-blocked IP addresses list and then you can unblock specific ip address or domain by using the "Delete" button under "Actions" and then confirm by clicking on the "Remove IP" button.