How do I add a phone number to my account?

For a personal Microsoft account, a phone number can no longer be added as a new security method. If the phone number was deleted from the account’s security info, the available replacement methods are:

1. Go to the Microsoft account Security tab.
2. Select Manage how I sign in.
3. Select Add a new way to sign in or verify.
4. Add one of the available methods, such as:
   • an email address
   • Microsoft Authenticator
   • a passkey

Important details:

• The option to add a new phone number may not appear for a personal Microsoft account.
• Microsoft notes that phone numbers may no longer be available as a new sign-in or verification method.
• If the goal is to add a phone number as a sign-in alias instead of a security method, only one mobile number can be used as a sign-in alias for a Microsoft account.
• If that number is already linked to another Microsoft account, it must be removed from the other account first, or transferred when the Transfer option is available.

If the number is already tied to another Microsoft account:

1. Sign in to the account that currently has the phone number.
2. Select Remove next to that phone number.
3. Sign out.
4. Sign in to the account that should use the number.
5. Select Add phone number.

If Transfer is shown when adding the number, that can be used instead. If Transfer is not shown, the number was recently used on another account and a different number must be used, or wait 30 days and try again.

References:

• Microsoft account security info & verification codes | Microsoft Support
• Help with reusing phone numbers in a Microsoft account | Microsoft Support
• How to add my phone number back to my account - Microsoft Q&A