Each machine connected to the web has a unique IP address which consists of 4 sets of numbers separated by full stops, for example 215.176.232.153.
This may be good for the machines but us humans are not very good at remembering numbers so we use easy to remember addresses instead, called urls. DNS, or Domain Name Service is the system by where your website url is resolved to the server your website is hosted on. It changes the human readable address such as https://www.hapihhost.in/ to a machine readable IP address.