What are request and response in client-server architecture?

In client-server architecture:

• Request - is a message sent by the client to the server to obtain information, perform an action, or modify data. It specifies what exactly the client wants to receive or do. It contains the method (GET, POST, etc.), the URI/URL of the resource, headers (content type, authorization, etc.), and optionally a body (for POST or PUT methods).
• Response - is a message sent by the server to the client in response to the received request. It contains the response status (e.g., 200 OK, 404 Not Found, 500 Internal Server Error), headers (content type, date, etc.), and optionally a body (e.g., requested data in JSON, HTML, or XML format).

They are the main units of data exchange between the client and the server.