add phone number to account

To add a phone number to an existing Microsoft account, the steps depend on what the number will be used for:

1. For a sign-in phone number or alias:
   • Go to Sign in.
   • Select Add phone number.
   • Complete the prompts.
2. If the number is already attached to another Microsoft account, only one account can use that mobile number.
   • Sign in to the account that currently has the phone number.
   • Select Remove next to that phone number.
   • Sign out.
   • Sign in to the account that should use the number.
   • Select Add phone number.
3. If a message says the number is already used to sign in:
   • Select Continue if that number already belongs to another Microsoft account that is already being used to sign in.
   • Select Transfer if the number should be moved to the current account.
   • If Transfer is not available, select Change number and use a different mobile number. If the number is new, try again after 30 days.
4. For Microsoft Teams Free, adding a mobile number to the Microsoft account lets that number be used as a sign-in alias, but only one mobile number can be used as a sign-in alias for an account.
5. If more help is needed, use contact support.

References:

• Help with reusing phone numbers in a Microsoft account
• Adding your phone number to a Microsoft account in Microsoft Teams Free