cloud service models is categorize into three way.
1 Software as a Service (SaaS)
2 Infrastructure as a Service (IaaS)
3 Platform as a Service (PaaS)
Software as a Service (SaaS)
The capability provided to the user is to use the provider’s applications running on a cloud infrastructure. It refers to a software that is deployed on a host service and is accessible via Internet.The applications are accessible from various client devices through either a thin client interface, such as a web browser (e.g., web-based email,Dropbox,Microsoft Office), or a program interface.
Characteristics of SaaS:
1-The software applications are maintained by the provider.
2-SaaS makes the resources available over the Internet all the time.
3-They are available on demand.
4-They can be scaled up or down on according needs.
5-They are automatically upgraded and updated