Cloud computing provides on-demand access to shared computing resources like networks, servers, storage, applications and services available over the internet. It has three main types of service models - Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as a Service (SaaS). IaaS provides basic storage, networking and computing resources, PaaS provides development tools and environments for building applications, and SaaS provides users access to applications over the internet. The document discusses these service models and their examples in more detail.