This feature for securing your account is part of the your Azure AD user settings, which requires you committing changes there.
You have 4 options, you can chose from receiving the Microsoft Authenticator Token:
- Authentication Phone
- Office Phone
- Alternate authentication phone
- Authenticator app
Either one or multiple Authenticators you might have set and need to change them according to your need.
- Sign in to https://myapps.microsoft.com
- Select your account name in the top right, then select profile.
- Select Additional security verification.
IMPORTANT SECURITY ADVICE:
It is important to configure a secondary authentication phone number. Because your primary phone number and your mobile app are probably on the same phone, the secondary phone number is the only way you will be able to get back into your account if your phone is lost or stolen.
3. Click "Additional security verification"
4. Change the Phone number to the new and add the secondary phone number