How to map custom domain to public ip

Hi,
i created VM behide Azure Load Balancer. i want to use custom domain to Load Balance Public IP. for example i want to access url like 'xx.mvg.com' instead Load Balance Public IP from internet. how i can do it?
i tried to did followed reference link 'https://docs.microsoft.com/en-us/azure/dns/dns-custom-domain' but still not working.
Please recommend how to register my domain name i wish, i want map my domain name to my application running on VM behide Azure Load Balancer.
and Azure have service about internet domain registrar?
Thanks You,
za_phu