Cloud computing architecture enables organizations to reduce or eliminate their reliance on an on-premises server, storage, and networking infrastructure.

Organizations adopting cloud architecture often shift IT resources to the public cloud, eliminating the need for on-premises servers and storage, reducing the need for IT data center real estate, cooling, and power, and replacing them with a monthly IT expenditure.

This shift from capital expenditure to operating expense is a major reason for the popularity of cloud computing today.

There are three major models of cloud architecture that are driving organizations to the cloud. Each of these has its own benefits and key features. 

Software as a Service (SaaS): SaaS architecture providers deliver and maintain applications and software to organizations over the Internet, thereby eliminating the need for end users to deploy the software locally. SaaS applications are typically accessed via a web interface available from a broad variety of devices and OSes.

Platform as a Service (PaaS): In this cloud model, the service provider offers a computing platform and solution stack, often including middleware, as a service. Organizations can build upon that platform to create an application or service. The cloud service provider delivers the networks, servers, and storage required to host an application while the end user oversees software deployment and configuration settings. 

Infrastructure as a Service (IaaS):In this, cloud at its simplest form, a third-party provider eliminates the need for organizations to purchase servers, networks, or storage devices by providing the necessary infrastructure. In turn, organizations manage their software and applications and only pay for the capacity they need at any given time.