commit
A saved snapshot of your project with a short message, so you can track changes and go back if needed.
Like a receipt that lists what you bought today and when. In Git, a system that tracks file changes over time, a commit saves the edits you made along with who made them and a message that explains why.
Commits matter because they let you review work, share it for feedback, and undo mistakes without drama. Small, focused commits make code review easier and help the agent or a teammate understand your intent.
In practice you write a clear message, save a commit, then send it to GitHub, which is an online place to store and share your code. Each commit has a long id you can copy to refer back to it. Never include secrets, which are private keys that control services, in a commit.