In the admin area settings, you can find various options for your GitLab instance like sign-up restrictions, account limits and quota, metrics, etc.
Navigate to it by going to Admin area > Settings. Some of the settings include:
- Account and limit settings
- Continuous Integration and Deployment
- Sign up restrictions
- Third party offers
- Usage statistics
- Visibility and access controls
- Custom templates repository
Most of the settings under the admin area change the behavior of the whole GitLab instance. For GitLab.com, the admin settings are available only for the GitLab.com administrators, and the parameters can be found on the GitLab.com settings documentation.