For a beginner, I'd probably stick to Github initially, just because there's so many guides and tutorials on how to use it, and their free plan is still pretty generous.

A lot of the knowledge is transferable though. If you do want to try something else, Codeberg is pretty good for open-source.

To just learn about Git, you don't even need a host like Github or Codeberg. You can have a Git repo just on your computer, and still get a bunch of the benefits of source control - a full history of everything, separate branches and worktrees so you can have multiple incomplete changes and switch between them, etc.