Cloud computing is all about how we can use external services over network by various resources provided by many different companies that share and access through the internet to perform many commercial essentialities. Cloud computing is combination of software and hardware applications as well as resources. Technological and Non-Functional, both aspects of cloud computing are deeply involved in cloud deployment, as cloud systems are of very powerful commercial nature. In this paper we emphasis on exploring the three major fundamental aspects of Cloud computing and deployment and service models of Cloud computing. We also explored Cloud computing applications in various areas.