Cloud computing delivers computing resources as a service over the internet. Users access cloud-based applications through a web browser or mobile app, while software and data are stored on remote servers managed by cloud providers. There are three main cloud service models: Infrastructure as a Service provides basic computing resources; Platform as a Service provides operating systems and platforms; and Software as a Service provides applications without requiring users to manage infrastructure. Public clouds offer services to the general public, while private clouds are for internal use within an organization.