You can download GIT for either Windows or MAC from the GIT website
Download the installer for your platform and run it. Once the install completes, you will be able to use GIT via a command line.
You'll use GIT through the built in Terminal App (BASH shell).
You'll see a new program called GIT Bash in your start menu. This will provide you with a limited BASH shell to use GIT.
Once you are familiar with GIT via the command line interface, you can explore some of the third party graphical based apps for GIT. Addtionally, VS Code has GIT support built in to its interface.