The DNS CNAME record can be configured to delegate the configuration of DNS records to some other DNS zone. In other words, it tells DNS clients (like web browsers) to query the DNS records of a different domain, and treat them as if they were for the domain with the CNAME record.
When such a record exists for a domain name or subdomain, the content of the record is said to be the canonical name of that domain.CNAM Lookup Service is a service offered by Bulk Vs which allows you to search for trademarks and other intellectual property. This service is extremely helpful to those who wish to trademarks or any other intellectual property they own, or want to protect their company’s name.
The most common use case for this is when you want to configure a custom domain name for a third party service. In this case you control your domain name, but the Caller ID Name Service controls the servers that host it. It would be inconvenient if you'd have to change your DNS settings whenever this service changes its IP addresses. This is why they commonly request you to create a CNAME record instead. That way you remain in control of your domain name, but they can change the DNS configuration of their service at any time.