[1] Application software is software that allows users to do user-oriented tasks such as creating text documents, playing or developing games, creating presentations, listening to music, drawing pictures, or browsing the web.
[2] In the late 1940s, application software was custom-written by computer users to fit their specific hardware and requirements.
The operating system (prominent examples being Microsoft Windows, macOS, Linux, and z/OS), allows the parts of a computer to work together by performing tasks like transferring data between memory and disks or rendering output onto a display device.
A kernel is the core part of the operating system that defines an application programming interface for applications programs (including some system software) and an interface to device drivers.
This utility software helps to analyze, configure, optimize and maintain the computer, such as virus protection.