Cannot add a phone number in my Account info

For personal Microsoft accounts, a new phone number may no longer be available as a sign-in or verification method. On the Security page, when selecting Manage how I sign in and then Add a new way to sign in or verify, the phone option might not appear. In that case, use one of the available methods instead, such as a recovery email address, Microsoft Authenticator, or a passkey.

To check:

1. Go to Sign in on the Microsoft account Security tab.
2. Select Manage how I sign in.
3. Select Add a new way to sign in or verify.
4. If phone number is not offered, add one of the available methods shown there.

If the issue is specifically that the new phone number is already tied to another Microsoft account, a phone number can only be added to a single Microsoft account:

• If the number is on another account owned by the same person, remove it from that account first, then add it to the target account.
• If Transfer is shown, use Transfer to move the number.
• If Transfer is not shown, the number was recently used on another Microsoft account. In that case, use Change number and a different number, or try again after 30 days.

If a recently added number is linked to a different account, the only option is to use a different mobile number.

If sign-in help is needed, use the Sign-in helper. For technical support, use Contact Microsoft Support.

References:

• Microsoft account security info & verification codes
• Help with reusing phone numbers in a Microsoft account