Like a telephone directory, a domain name system (DNS) bridges the gap between humans and computers by linking domain names to their respective Internet Protocol (IP) addresses.
You want to go to the ai4k.eu website, so you enter the domain name ai4k.eu in the address bar of your web browser. What you are doing here is sending a DNS request.
The function of a domain nameserver is to store all DNS records for a domain name. Every time someone sends a query about your domain name, the nameserver returns the information corresponding to your domain name, allowing them to find your website.
In practice, nameserver addresses often point a domain name to a hosting account through DNS services.
This action is unnecessary if you have purchased a domain name from a hosting provider. But it must be done if the domain registrar is not the same as your hosting provider.
For example, if you host a website at Elementor Cloud but own a domain from Namecheap, you will have to change the DNS address to Elementor Cloud. Only then will the domain name be connected to the website.