Why is Office 365 is asking for cell phone numbers or alternate email address?

Charter has implemented a new self service password reset option in Office 365

The next time you sign into Office 365 you will be prompted to enter a cell phone number or an alternative email address. If you do not enter one of these options you will not be able to utilize this self service password reset.

Once you have set this up, if you forget your password and can’t log in you will be able to reset your Office 365 password without help from the school.