repository
Like the main project folder everyone shares, it holds all the files and history for your app’s code on a service like GitHub.
Think of a shared binder that keeps every page and every past version. A repository is the online home for your code and its history so teammates and tools can work together.
It matters because you can track changes, discuss them in pull requests, roll back when something breaks, and connect services that test or deploy your app.
In practice you commit, which is saving a set of changes with a message, create branches for separate tasks, open pull requests for review, and protect the main branch so only reviewed code is merged.