AWS Cloud can be adopted in three modes – Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS).
IaaS offers networking, computing resources and data storage. It provides a flexible environment to adopt Cloud and control the Cloud resources. It is more similar to the As-Is IT estate which is deployed to the Cloud through containerization.
PaaS focuses only on deployment and management of native cloud applications as hardware and operating systems are already a part of the PaaS mode of cloud adoption. It resolves the hassles for resource procurement & capacity planning, maintenance, and software & security patching.
SaaS offers end-user applications in pay per use model. It resolves the hassles for service and infrastructure maintenance, such that the end-users can only focus on using the software application.