Commits are snapshots of your project at a point in time. Each commit has a unique hash, an author, a timestamp, message, and the full state of all tracked files. You can view history, revert to old commits, and understand who changed what and why.

$ git add file.txt           # stage a file
$ git commit -m "message"    # create a commit from staged changes
$ git show <hash>            # view a commit's changes
$ git revert <hash>          # create a new commit that undoes an old one

Commits are immutable once created—you cannot change a commit's content or message without creating a new commit. This makes history reliable and auditable. Always write clear commit messages that explain the “why”, not just the “what”.