For G Suite.
For Office 365.
Am I able to configure an expiration period for the end users' passwords?
You can change the password expiration date by combining these two items.
Password expiration date:
You can set any period you like (1 to 366 days).
Notification of password expiry:
You can use 4 patterns below.
・Display warning message
・Force to change password
・Lock out (makes the user unable to login)
About the settings above, you can exclude the administrator.