Repositories are folders managed by git. Initialize one with git init to start tracking changes. Git stores its metadata in a hidden .git/ subdirectory. Every developer gets a full copy of the repository including all history, so you can work offline and sync with others when ready.

$ git init                  # create a new repository
$ git clone <url>           # copy a remote repository locally
$ git status                # show current state

A repository contains your project files plus git's tracking data. The .git/ folder is where git stores all commits, branches, configuration, and other metadata. Treat it as sacred—deleting it loses your entire history.