Creating Custom Name Servers with Domain on WHM cPanel
Ensure that your domain registrar allows you to create custom nameservers with your domain name.
Choose the prefix you wish to use with your domain, e.g. ns1.yourdomain.com ns2.yourdomain.com
Set them up using the two IP addresses that you have for DNS at the registrar domain manager. You will need to contact you provider to obtain these IP addreses.
Ask your data centre to enter a reverse DNS pointer for your nameservers.
Now--> WHM-->>Server Setup >> Enter ns1.yourdomain.com in the Primary Nameserver field. Hit 'Assign IP Address', then hit 'Add an A Entry for this nameserver'. Repeat this process for Secondary.