Scoop is a package manager for Windows. It enables you to install and update applications and services via the command line - just like you would install packages on MacOS, Linux or in PHP via Composer.
Your Windows system should already come with some packages installed, e.g.
Most of these are installed system wide and some of them are also installed as a service.
To find out more about Scoop, simply look at its Wiki. Usually you will not have to deal with Scoop yourself, but you are free to install any applications via Scoop.