Once the domain or subdomain name points to the IP address, follow these steps:
Step 1: Log into cPanel and navigate to the Zone Editor within the Domains section.
Step 2: Click on the MX record button and enter your priority in the Priority field, with a lower value being a higher priority and zero being the highest.
Step 3: Then input your domain or subdomain name in the Destination field, then hit Add an MX Record.
Important Note: You will need to configure your Mail routing to a remote mail exchanger if your MX record points to an external server: