The client-server model is a distributed system, where one server provides services and resources to multiple clients. Like a restaurant-server provides resources (i.e., food, drinks) and services (i.e., welcoming customers, explaining menu) to many dinners. Web servers, FTP (File Transfer Protocol) Servers, and the Internet are examples of services that use the client-server model.
Example
It works with a request-response architecture where clients send requests to servers, then servers send clients responses. Web browsers send HTTP requests to web servers for web data and the web servers send back HTTP responses.