This document provides an overview of cloud computing, including its basic functioning, characteristics, service models (IaaS, PaaS, SaaS), types of clouds (private, public, hybrid, multi-cloud, community), and advantages and disadvantages. Cloud computing allows on-demand access to shared configurable computing resources via the internet. It provides various capabilities for users to store and process data in third-party data centers. The main service models are infrastructure as a service, platform as a service, and software as a service.