Cloud computing supports following deployment models:

Private Cloud: Some companies build their private cloud. A private cloud is a

fully functional platform that is owned, operated and used by only one

organization.

Primary reason for private cloud is security. Many companies feel secure in

private cloud. The other reasons for building private cloud are strategic

decisions or control of operations.

There is also a concept of Virtual Private Cloud (VPC). In VPC, private cloud

is built and operated by a hosting company. But it is exclusively used by one

organization.

Public Cloud: There are cloud platforms by some companies that are open for

general public as well as big companies for use and deployment. E.g. Google

Apps, Amazon Web Services etc.

The public cloud providers focus on layers and application like- cloud

application, infrastructure management etc. In this model resources are shared

among different organizations.

Hybrid Cloud: The combination of public and private cloud is known as

Hybrid cloud. This approach provides benefits of both the approaches- private

and public cloud. So it is very robust platform.

A client gets functionalities and features of both the cloud platforms. By using

Hybrid cloud an organization can create its own cloud as well as they can pass

the control of their cloud to another third party.

https://www.geeksforgeeks.org/cloud-deployment-models/