How Browsers & Servers Communicate.

HTTP headers are the control Language i.e. a medium or channel in which communications happen between BROWSERS & SERVERS on the internet. When you make a request using a Browser. for example www.example.com. The Http Header sends a GET request to the server asking for DATA. The Http now queries the Whole of the internet through DNS(Domain Name System) to find WWW.example.com. Http Headers are General, Client Request, Server Response and Entity headers.

In Security,Headers are used to Block Malicious Request from Threat actors through the help of Web Application Firewall.