About branch restrictions
Branches within repositories that belong to organizations can be configured so that only certain users or teams can push to the branch.
Protected branches are available in public repositories with GitHub Free, and in public and private repositories with GitHub Pro, GitHub Team, GitHub Enterprise Cloud, and GitHub Enterprise Server. The ability to restrict branches is a type of branch protection that's available for public and private repositories owned by organizations in GitHub Team, GitHub Enterprise Cloud, and GitHub Enterprise Server.
When you enable branch restrictions, only users or teams that have been given permission can push to the protected branch. You can view and edit the users or teams with push access to a protected branch in the protected branch's settings.
You can only give push access to a protected branch to users or teams with write access to a repository.
People with admin permissions to a repository are always able to push to a protected branch.
Note: If "Include administrators" is selected, you've enabled required status checks on the branch, and status checks fail, any attempt to push changes to the protected branch will also fail, even for people with admin permissions.