I know that for every HTTP request the request carry some request header parameters like Accept, Accept-Languate etc..

I understand the general meaning of those parameters. But how server utilizes that information, that is not yet unclear. For example, The request header "Accept" header means "Content-Types that are acceptable". And for example I have set "Accept": "text/html". What server will do with that information? It understands that client only accepts "text or html" response only and hence it will avoid to send other type of responses for that request. Is it like that? Am I right? Please help me to understand better

What we are informing server with these attribute values? How server utilises this information?

Similarly HTTP response also carries some response parameters? What server would like to inform client with these parameters and how client uses those parameters.

If any body has idea please explain.

You can read the spec on how the server should interpret them.