HTTP Stands for Hyper Text Transfer Protocol and it’s a way of communicating between web browsers and web servers.
One of the ways that http is used to communicate between web browsers & web servers is http status code, It provides a number that represent the current state of the operation in the webpage.
Here are some examples:
Informational responses (100–199)
Successful responses (200–299)
Client errors (400–499)
Server errors (500–599)
If you want to read more, These links will do the work: