Trusted documents – Microsoft Support

Making changes starts or disables the ability to create trust documents that protects your computer and your organization’s network from possible malicious code in active content. Click the File tab. Click Options. Select Trust Center, and then Trust Center Settings. Click Trusted Documents.

https://support.microsoft.com/en-us/office/trusted-documents-cf872bd8-47ec-4c02-baa5-1fdba1a11b53?ns=powerpnt&version=90&syslcid=1033&uilcid=1033&appver=zpp900&helpid=121533