Cloud computing plays a significant role in the world of computers. It is a modern technology that provides a fast access mechanism, expandable, reliable, and provides user specific-facilities such as software services and infrastructure. Through the Internet, the user can access resources wherever they are, so this technology is beneficial in their daily lives. Cloud services provided by the cloud (SAAS, PAAS, IAAS) enable the user to access programs and the platform. Security is the main problem facing the cloud, so people think that using the cloud and its services is not safe, as there is no guarantee of stored information. Distributed computing is a computer division that explores distributed systems, and a distributed system is a system. That exists on computers connected to the network to be communicated through messages passed between each other. Using distributed computing systems has increased due to lower hardware costs and advances in computer network technologies. Distributed computing systems provide the potential for better efficiency and sharing of resources. This article will give a brief overview of cloud history computing, its evolution, advantages, and security aspects, as well as the history of distributed computing, its structure, applications, benefits, and disadvantages.