Platform-as-a-Service (PaaS) is a cloud computing model that provides developers with a platform to build, deploy, and manage applications without worrying about the underlying infrastructure. It offers tools and services such as databases, development frameworks, and middleware, allowing developers to focus on coding and application functionality. PaaS simplifies the development process by providing a ready-to-use environment that supports various programming languages and frameworks. This model is beneficial for businesses as it reduces the time and cost associated with software development, enabling faster innovation and easier collaboration among teams.