Microsoft has announced that Application Guard for Office is now generally available for all Microsoft 365 users with supported licenses. Application Guard blocks files downloaded from untrusted sources from gaining access to trusted resources by opening them in sandboxes. Microsoft will enable fully automated threat remediation by default for Microsoft Defender for Endpoint customers who opted into public previews starting next month. Microsoft provides instructions on how to deploy and configure Application Guard. It works with Word, Excel, and PowerPoint for Microsoft 365 and it will be toggled off by default.
Source: https://www.bleepingcomputer.com/news/security/microsoft-rolls-out-application-guard-for-office-to-all-customers/