Hi,
There are 2 way for the Notify Active Directory Users about Password Expiry
One: Email Notify Active Directory Users about Password Expiry using PowerShell
This way ,we need to deploy a script to trig the notify, more details you can refer to:
https://social.technet.microsoft.com/wiki/contents/articles/23313.notify-active-directory-users-about-password-expiry-using-powershell.aspx
Two: Inactive logon notify
Navigate to Computer Configuration → Windows Settings → Security Settings → Local Policies → Security Options.
Select the policy named as “Interactive Logon: Prompt user to change password before expiration”.
With this policy, whenever your Windows computer connects to the domain the warning logon message - “Your password will expire in 5 days. Do you want to change it now?” will appear on the screen if your password is nearing its expiration date. Click “Yes” if you want to change it now and “No” if you want to change it at another time.
Best Regards,