Providing the users with the computing platforms which typically includes operating system, programming language execution environment, database, web server etc. is known as PaaS (Platform as a Service). AWS (Amazon Web Services) a comprehensive, evolving cloud computing platform provided by Amazon is a good example of PaaS.
Using the full potential of a platform helps eliminate the expense of purchasing, configuring, and managing the hardware and software required for custom-built applications. With a platform, new features, capabilities and bug fixes are served automatically over the cloud. This way, companies can focus more on core business rather than maintaining their IT infrastructure.