Just like any other features in Windows, the Group Policy settings are also available for Microsoft 365 Apps for enterprise, Office 2021, Office 2019 and Office 2016. If you are an IT person, you can use Administrative Templates from Microsoft. It allows you to apply organization-wide policies.
Download Administrative Templates for Office 2021 and Microsoft 365
There are two ways of applying policies for these products. One is through Active Directory Domain Services, and the second uses Office Customization Tool (OCT).
If your organization uses Windows Server and Active Directory Domain Services (AD DS), you can configure settings via Group Policy. Copy the ADMX/ADML files into the AD DS environment and set it using Group Policy Management administrative tool. ADMX files are registry policy settings that provide an XML-based structure. So anything you change there updates the registry.
If you are using the OCT, copy the admin folder(which contains OPAX/OPAL files) into Office installation files. OCT is used when you have the volume-licensed edition of Office. It is available for both x86 and x64 system. It includes-
1] Group Policy Administrative Template files (ADMX/ADML): These files are used by Group Policy to configure installations of Office 365 products, such as Office 365 ProPlus, and volume-licensed versions of Office.
2] There is an additional admin folder with OPAX/OPAL files. These files are used by the Office Customization Tool (OCT). This admin can customize Windows Installer (MSI) installations of volume-licensed Office.
3] It also includes Office2016GroupPolicyAndOCTSettings.xls which is a list of all the Group Policy and OCT settings.
You can download it from microsoft.com.
What is an administrative template?
Administrative templates are configuration settings that can be used to manage Windows operating systems and applications. These templates centrally manage various security policies, user preferences, and system configurations across an organization. IT admins usually use them.
What are ADMX and ADML files?
Administrative templates consist of two parts: an ADMX file, which contains the actual settings, and an ADML file, which contains the language-specific settings. These templates can be accessed through the Group Policy editor, allowing administrators to modify user and computer configuration settings.
TIP: Group Policy Analyzer from Microsoft lets you analyze, view and compare sets of Group Policy Objects (GPOs) in Windows OS.