It refers to the software that an organization uses (either licensed or subscription based). So why do we use them? Because developing yourself will be too expensive.
Advantages of using 3rd party software
SaaS is a method of software delivery where applications are hosted remotely by a vendor and are made available. Simply put, companies rent the software rather than buying or developing it. Although it is a departure from the conventional method of purchasing software, it can provide many notable advantages, particularly through: access to expensive, high-powered software which is otherwise unobtainable; reduction of extra work hours and downtime that might have been necessary to develop your own solution; no scaling and compatibility issues. All in all, SaaS is safe and secure, particularly with an IT specialist who can configure, manage it and ensure that data is protected.