If you want to use GitHub Advanced Security features in a private or internal repository, you need a license for your enterprise. These features are available free of charge for public repositories on GitHub.com.
GitHub Advanced Security is available for enterprise accounts on GitHub Enterprise Cloud and GitHub Enterprise Server. Some features of GitHub Advanced Security are also available for public repositories on GitHub.com. For more information, see "GitHub’s products."
If you want to use GitHub Advanced Security features on any repository apart from a public repository on GitHub.com, you will need a GitHub Advanced Security license, available with GitHub Enterprise Cloud or GitHub Enterprise Server.
For information about billing for GitHub Advanced Security, see the GitHub Enterprise Cloud documentation.