@Wuming Jin Thank you for reaching out to us, As I understand you are looking for an option to setup email notifications for Azure AD Connect Health, Refer to this article - https://learn.microsoft.com/en-us/azure/active-directory/hybrid/connect/how-to-connect-health-operations it has the steps to configure email notifications.
Before enabling the email notifications, you need to configure the agent for sync - https://learn.microsoft.com/en-us/azure/active-directory/hybrid/connect/how-to-connect-health-agent-install#install-the-agent-for-sync:~:text=AD%20FS%20auditing.-,Install%20the%20agent%20for%20sync,-The%20Azure%20AD
Let me know if you have any further questions, feel free to post back.
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