A domain name system is what makes it possible to translate a URL into an IP address and vice versa.
Information about domain names is stored in the form of databases on servers around the world.
Every time you want to visit a website, your web browser contacts one of these servers, which returns your requested webpage along with its corresponding IP address (which is like your computer’s mailing address).
As requests are made for each page within site, similar actions occur.
Each successive request may result in another server being contacted until, eventually, all pages comprising the complete site have been retrieved by the browser.
When you enter a URL into your browser, such as www.example.com, that particular URL will be turned into an IP address before being passed along to the DNS server for resolution.
The result is that your browser and the website you are visiting will communicate with each other using IP addresses instead of URLs, which makes things a lot easier for everyone involved.