Why it matters
In a DevOps team, Git is not just where code is saved. It is the starting switch for everything: a push starts the tests, a merge starts a deployment, a tag starts a release. Adverts name Git, GitHub and GitLab because a team's Git habits decide whether its pipelines are calm or chaotic. If Git is new, finish Git and GitHub in the backend track first.
Branches and pull requests
Nobody works directly on the main branch. You make a short lived branch, commit small changes and open a pull request (GitLab calls it a merge request) asking to merge into main:
git switch -c fix/receipt-total
git add receipt.js
git commit -m "Fix rounding in receipt total"
git push -u origin fix/receipt-totalOn GitHub you then open the pull request, describe what changed and why, and ask a teammate to review.
Code review
A reviewer reads the change, asks questions and suggests improvements. Good reviews are kind and specific: "This loop runs once per customer; could we fetch them in one query?" rather than "this is bad". Reviews catch bugs, spread knowledge and stop any one person being the only one who understands a system.
Protecting main
Teams turn on branch protection so nobody can push straight to main. A pull request can only merge when the pipeline's checks pass and at least one reviewer approves. This one setting turns good intentions into a rule.