The name identifies your address
A domain is the name you register for a period of time, such as `example.com`. Registration determines who controls the name and when it must be renewed. Owning the domain does not automatically configure a website, mailbox, or other service to answer at that name.
A domain can also contain subdomains, such as `shop.example.com` or `mail.example.com`. These names can direct different types of traffic to different services while remaining under the registered domain. Choosing a useful hostname is separate from deciding which records should serve it.
The zone tells services where to go
A DNS zone contains records that map names to destinations or describe how a service should be handled. Website records and mail records serve different purposes, and verification records may be needed as well. Changing the zone can therefore affect several services even when the registered domain itself does not change.
Before connecting a domain or changing nameservers, list the records your existing website, mail provider, and subdomains rely on. Review the destination zone and preserve needed values before switching. This distinction prevents a common mistake: treating a domain purchase, a domain connection, and a DNS migration as if they were the same operation.