Therefore, when you change your phone number or alternative email address, be sure to change the phone number or alternative email address linked to your Microsoft account as well.
It’s a good idea to keep the phone number and alternative email address associated with your Microsoft account to up-to-date. The alternative email address and phone number will be used when you want to change or reset forgotten Microsoft account password or to alert you if Microsoft finds suspicious activity on your account. While creating a Microsoft account, the sign-up page asks you to add an alternative email address and a phone number as security information to your Microsoft account.
