When a member of your organization creates a new repository, GitHub will create a single branch and set it as the repository's default branch. GitHub currently names the default branch
master, but you can set the default branch to be named anything that makes sense for your development environment.
If you have admin permissions to a repository, you can change the default branch to another existing branch. For more information, see "Setting the default branch."
While you can rename your repository's existing default branch, GitHub plans to provide tools to simplify the process of renaming the default branch. For more information on these plans, see
If you have already renamed the default branch, GitHub will automatically redirect links on GitHub.com that contain a deleted
master branch name to the equivalent link on the repository's default branch.
In the top right corner of GitHub, click your profile photo, then click Your profile.
On the left side of your profile page, under "Organizations", click the icon for your organization.
Under your organization name, click Settings.
In the left sidebar, click Repository defaults.
Under "Repository default branch", click Change default branch name now.
Type the default name that you would like to use for new branches.