Final answer:
To view which users have used an authenticator app to access SharePoint Online, you should access the Azure Active Directory sign-in logs in the Azure portal. Use the filter options to specify sign-ins with an authenticator app and SharePoint Online as the service.
Step-by-step explanation:
To view which users have used an authenticator app to access Microsoft SharePoint Online while minimizing costs, you should access the Azure Active Directory (Azure AD) sign-in logs. Since you have a Microsoft 365 E5 subscription, you can utilize Azure AD's built-in reporting features without incurring additional costs.
Here are the steps you can follow:
- Go to the Azure portal.
- Navigate to Azure Active Directory.
- Select Sign-ins from the monitoring section.
- Use the filter options to specify sign-ins via an authenticator app and SharePoint Online as the service.
- Review the logs to identify the users.
Remember that Azure AD sign-in logs retain data for a limited time, typically 30 days for E5 subscriptions. To keep records for a longer period, you need to export them to another storage solution.