The three main types of cloud services are Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). IaaS provides virtualized computing resources over the internet, allowing users to rent infrastructure. PaaS offers a platform for developers to build, deploy, and manage applications without handling the underlying infrastructure. SaaS delivers software applications over the internet, enabling users to access them via web browsers without local installation, promoting flexibility and scalability.