Git is a program your computer runs to have a single folder have source control. It does all the hashing and commit chaining that you're used to, branches, that sort of thing.

But if you want it to be on more than one computer, you need to do this complicated "Bare" repository setup on a server computer to do the "git push" stuff you're used to.

Most people, being too lazy to learn bare repositories and the general sysadmin necessary to host a git server themselves, instead just use Microsoft's Github which is a web interface for the server use of git the program.

Microsoft then proceeded with their classic mantra of "Embrace, Extend, Extinguish" and started slapping on more and more features that are incompatible with any other git hosting service: actions, CI, their web VSCode instances, etc. That's all in GitHub too. But it's all just web interface for git the open source program, at the end of the day.