Click “settings” on your repository’s GitHub page
Click "Options" from the sidebar
Scroll down to "Danger Zone" section
Click "Change Visibility"
You can explicitly invite users to commit changes to your repository through adding collaborators:
On the repository page navigate to “settings”
Click “Manage access”
Click “invite collaborators” and type in the user name of the users you want to add.
As mentioned in the section, you can determine which users can see your repositories. If you set repository visibility to “Public” then anyone on the internet can read and download your repository. If you set repository visibility to “Private”, then only users or organizations you explicitly invite can read and download your repository. To change visibility of your repository:
Changing the visibility of your repository can affect your repository’s forks and must be done with caution (see article for more details).
