unable to add cell phone number to my profile in order to receive OTP when upgrading package

Hello, thank you for reaching out to Microsoft Q&A.

For security reasons, Microsoft has removed the option to add a phone number to your Microsoft account. Therefore, you can no longer use your phone number to verify your identity or receive OTP verification codes.

However, you can add other verification methods, such as a recovery email address, passkey, or the Microsoft Authenticator app. You can manage these security options by signing in to your Microsoft account here:

https://account.live.com/proofs/Manage

Also, may I please ask if you are having trouble upgrading your Microsoft 365 subscription? If so, could you please elaborate on the issue you are experiencing and let me know what happens when you try to upgrade?