User Configuration > Administrative Templates > Microsoft Word 2016 > Collaboration Settings > Co-authoring
User
HKCU\software\policies\microsoft\office\16.0\word\coauthoring
This policy controls whether users will be able to co-author Word documents with macros. Enabling this policy setting will turn off the ability to co-author Word documents with macros. If you disable or don't configure this policy setting, the user will be able to co-author Word documents with macros. Note: This policy setting only applies to subscription versions of Office, such as Microsoft 365 Apps for enterprise.