Cloud computing is changing how businesses operate by providing power, flexibility and cost savings. It delivers computing resources like software, storage and infrastructure over the internet on an as-needed basis. There are three main types of cloud computing models - Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). IaaS provides virtualized computing resources, PaaS provides development tools and platforms, and SaaS provides applications delivered over the internet. Major cloud providers include Amazon, IBM, Microsoft and Google who offer these cloud services to businesses.