A cloud computing infrastructure type where applications are hosted over a network (typically Internet) eliminating the need to install and run the software on the customer's own computers is known as Software as a Service (SaaS).
These are applications hosted over the internet so the user does not have to download them. An example is Google Apps, where you can access something similar to Microsoft Word or Excel, without having to download anything.
Software as a service (SaaS ) is a software licensing and delivery model in which software is licensed on a subscription basis and is centrally hosted. SaaS is also known as "on-demand software" and Web-based/Web-hosted software.SaaS is considered to be part of cloud computing, along with infrastructure as a service (IaaS), platform as a service (PaaS), desktop as a service (DaaS), managed software as a service (MSaaS), mobile backend as a service (MBaaS), data center as a service (DCaaS), integration platform as a service (iPaaS), and information technology management as a service (ITMaaS).SaaS apps are typically accessed by users using a thin client, e.g. via a web browser. SaaS became a common delivery model for many business applications, including office software, messaging software, payroll processing software, DBMS software, management software, CAD software, development software, gamification, virtualization, accounting, collaboration, customer relationship management (CRM), management information systems (MIS), enterprise resource planning (ERP), invoicing, field service management, human resource management (HRM), talent acquisition, learning management systems, content management (CM), geographic information systems (GIS), and service desk management.SaaS has been incorporated into the strategy of nearly all enterprise software companies.