Once you have your domain name, it really doesn’t do anything. This is where DNS or Domain Name System is involved.
The Internet actually works on an addressing system that is a bunch of numbers like 192.168.0.123. It is called an IP address or Internet Protocol address. If you type the correct IP address into your web browser, that website will appear. However, it is not easy to remember those numbers so an easier system was created that involved words. Those words are the domain name.
But, there still needed to be a system to match the domain name to the IP address. That is DNS.
You will need to setup DNS records when you want to setup a website or email. Your website hosting company or email hosting company will list the information you need to enter or might even do it for you.