You may use the following procedure to make changes to the zone file template, which would be implemented for newly created domains.
Note, as domains can not be created on DNSOnly servers, you will not be able to edit zone file templates on DNSOnly servers. You will need to change the zone file template on the cPanel servers that are clustered to the DNSOnly server.
1. Login to WHM as the root user
2. Navigate to Home »DNS Functions »Edit Zone Templates
3. Click on the Standard template
4. Add or adjust the DNS entries to match the template you wish to use.
5. Click the blue Save button
You can find the format for creating templates in our documentation.