Kindly navigate to macOS–>Advanced Restrictions. On the bottom portion, you will be able to find the ‘App installation from’ option. It will have a dropdown list beneath it. Click on it and it will have the following two options:
Mac App Store: Allows app installation only from the Mac App Store
Mac App Store and identified developers: Allows app installation from the Mac App Store and identified developers.
Choose from these available options based on your requirements. Please note to associate targets and save the policy.