Infrastructure as a Service (IaaS) primarily provides users with storage, computing resources, and networking capabilities. In the IaaS model, cloud providers offer virtualized computing resources over the internet. Users can rent servers, storage, and networking equipment without needing to manage the physical hardware themselves. This allows for flexible scaling and resource management according to the users' needs.
FaaS focuses on serverless computing where users run code in response to events. PaaS provides a platform that allows users to develop, run, and manage applications without worrying about the underlying infrastructure. SaaS delivers fully managed applications over the internet, where users access software without managing the infrastructure.