In the top-right corner of GitHub Enterprise Server, click your profile photo, then click Enterprise settings.
In the enterprise sidebar, click Policies.
Under Policies, click Options.
Under "Users can create organizations", use the drop-down menu and click Enabled or Disabled.
This version of GitHub Enterprise will be discontinued on 2022-02-16. No patch releases will be made, even for critical security issues. For better performance, improved security, and new features, upgrade to the latest version of GitHub Enterprise. For help with the upgrade, contact GitHub Enterprise support.
Preventing users from creating organizations
You can prevent users from creating organizations in your enterprise.