A server is simply a computer which can process requests and send data to other computers via the internet or a local network; it can store and process information within its own system or request it from another. A cloud server typically describes a centralized server resource that is hosted over an interconnected network and accessed by multiple users on demand.

Servers come in many forms and perform a multitude of functions: for example, web servers deliver web pages and run apps via web browsers; FTP servers make files accessible remotely through File Transfer Protocol tools; proxy servers send data between host and client servers; cloud servers are virtual servers (rather than physical ones) that are accessible remotely over a network.
Servers perform a variety of functions (including file storage and database management) and are therefore vital for most business operations. Cloud servers perform all the functions of network servers, but as they often replace the need for an in-house network server they are typically a more cost-effective solution for businesses. They also offer complete flexibility to scale server resources as needed.
A server is a piece of hardware or software that offers a service to a computer program and its user (client). The actual computer that a server program runs on is usually referred to as a server in a data center. This device might operate as a dedicated server or fulfil other uses. A server programme in the client/server programming model listens for and processes requests from client programmes, which may be operating on the same computer or on different computers. In a computer, a particular software may act as both a client and a server, receiving requests for services from other programs.