I cannot add my phone number

The missing Add phone number option can be expected for a personal Microsoft account, so add a recovery email, Microsoft Authenticator, or a passkey first, then remove the other person’s number.

Replace the security method

1. Open the Microsoft account Security page:
   https://account.microsoft.com/security
2. Sign in and select Manage how I sign in.
3. Select Add a new way to sign in or verify.
4. Add one of the options shown:
   • A recovery email address you can access
   • Microsoft Authenticator
   • A passkey using your device’s face, fingerprint, or PIN
5. Complete the verification process.
6. Confirm the new method appears and works before selecting the unfamiliar phone number and choosing Remove.

Microsoft is phasing out SMS authentication and recovery for personal accounts, so the phone-number option might not appear at all. Verified email addresses and passkeys are the intended replacements.^1^ ^2^

If the other person’s number blocks access

If Microsoft asks for a code sent to that number and you cannot use another verification method:

1. Start signing in to the Microsoft account.
2. At Verify your identity, select I don’t have any of these.
3. Follow the prompts to replace the inaccessible security information.
4. After replacement, Microsoft imposes a 30-day waiting period before you can sign in normally. Using the old security information during that period cancels the requested update.^3^

Do not remove the existing number before adding and testing another method if you can still access the account. Also change the account password if the person who set it up knows it.

References

1. Microsoft account security info & verification codes | Microsoft Support
2. Microsoft to stop sending SMS codes for personal accounts
3. Troubleshoot Microsoft verification code issues | Microsoft Support