An integrated threat protection solution designed to detect, investigate, and respond to cyber threats across Microsoft 365 services.
This depend on whether you're using an iPhone or Android.
If you're using an iPhone
On iOS 18 or later: Locate the Outlook app on your Home Screen> Press and hold the Outlook icon> Select Require Face ID (or Touch ID).
Or in the Outlook app Settings > Toggle on the FaceID option.
If you're using Android
I don't think Outlook has a general, user-configurable biometric app lock for personal accounts on Android.
If this is a work or school Microsoft 365 account
Your IT administrator can use Microsoft Intune app protection policies to require a PIN or biometric authentication before users can access their work emails.