SaaS, or software as a service, is a cloud service model that provides ready-to-use, cloud-hosted

application software to customers. Customers do not need to install, manage, or maintain the

software; they simply access it via an internet connection, usually through a web browser. SaaS

applications are typically offered on a subscription or pay-per-use basis. Examples of SaaS

applications include email, CRM, ERP, office productivity, and collaboration tools12.

SaaS is different from the other cloud service models in terms of the level of abstraction and control.

In SaaS, the cloud service provider manages everything from the underlying infrastructure to the

application software, while the customer only controls the application settings and data. In contrast,

in IaaS (infrastructure as a service), the customer has more control and responsibility over the

servers, storage, networking, and operating systems, while the cloud service provider only manages

the physical infrastructure. In PaaS (platform as a service), the customer has control and

responsibility over the applications and data, while the cloud service provider manages the

underlying infrastructure and the development tools and platforms12.

Therefore, when an organization uses a third-party ERP tool as a complete service, it is using the SaaS

cloud service model. The organization does not need to worry about the installation, configuration,

or maintenance of the ERP software; it only needs to access it via the internet and pay for the

usage. The cloud service provider takes care of the rest.

https://www.comptia.org/training/books/cloud-essentials-clo-002-study-guide

https://www.amazon.com/CompTIA-Essentials-Certification-Second-CLO-002/dp/1260461785