Password change notification email
In order to help keep your account secure, Google sends you an email any time your password is changed. If you made this change, you won't need to take any action.
If you receive a notification about a password change that you did not make, someone else might have accessed your account and changed your password. To keep your account secure, you should reset your password immediately using your recovery options, and make sure to choose a strong password.
If the notification is about a password change for an account that does not belong to you, someone might have accidentally typed in your email address when attempting to type in their own email address. In this case, this password change does not affect your account, and you do not need to take any action. In some cases, you might see a link at the bottom of the notification email that you can click to remove your email address from the other person’s account.
There is currently no setting to turn off password change notification emails, as they are important to ensure the security of your account.