Cloud computing is the delivery of computing services such as software, platforms, and infrastructure over the Internet.
It can be classified into three types:
Software as a Service (SaaS). Where the cloud provider hosts an application or software, which you then use over the web.
Platform as a Service (PaaS). Where the cloud provider hosts a platform that you use to develop and run your own applications.
Infrastructure as a Service (IaaS). Where the cloud provider hosts your servers and provides access to storage and other resources you need to build and run your own applications.
