A virtual private server(VPS) is a machine that hosts all the software and data required to run an application or website. It is called virtual because it only consumes a portion of the server's underlying physical resources which are managed by a third-party provider. However, you get access to your dedicated resources on that hardware.
A dedicated server is a physical server that's assigned to a single organization. You need a server to host or run your applications and websites so that your users can access your services.
Cloud servers are virtual (not physical) servers running in a cloud computing environment that can be accessed on demand by unlimited users. Cloud servers work just like physical servers and they perform similar functions like storing data and running applications.