A version-controlled repository is the shared project store that holds a team's files, including documentation, and records every revision. Teams use it so they can work in parallel without overwriting each other, recover a prior version if work is lost, and see what changed, why, when, and by whom. User stories describe the functionality to build and are often called tickets or work items; documenting them in that versioned store, and tying commits to those stories, is how the team keeps scope visible and chooses what belongs in a release.