Go in your online repository in your web browser (example: https://github.com/mycompany/trailheadapps/dreamhouse-lwc)
Go to the Pull Requests tab
Click on New pull request
Select the base as the target environment/branch and compare as the branch you've made the changes. Click Create Pull Request
Add a meaningful title and description. Click on Create Pull Request
Controlling jobs are automatically launched, you can now ask your release manager to validate the merge request
If you are a developer, (or even a business consultant depending on the project organization), you may have the responsibility to make sure than controlling jobs are valid (check-deploy job and code-quality job in success) and eventually fix the errors (See Handle merge requests errors)
If you need to add additional updates to an existing merge requests, you just this to follow again this guide from the beginning, except the part "Create a merge request". Any new commit pushed on a branch where there is already a merge request will trigger again the control jobs.
