DNS is a system that helps connect your services (think, email) with the underlying plumbing of the internet. DNS for your domain can usually be set up through your domain registrar.
DNS is an acronym for domain name system.
For example, DNS lets you type google.com into your browser, and have the correct page display. DNS translates your request to see google.com into a request for a specific IP address. An IP address is more difficult to remember than google.com. Under the hood, google.com is navigated to using its IP address, which is
Read more about DNS: https://www.cloudflare.com/en-ca/learning/dns/what-is-dns/