This new registration experience enables users to register for MFA and SSPR in a single, step-by-step process. When you deploy the preview experience for your organization, users can register in less time and with fewer hassles. In addition, the new My Profile experience provides users with a more streamlined and easier-to-navigate experience for reviewing and updating their profile info
From the Security info page, users can easily change their phone number or choose a different default method. From here they can also add, delete, or change a method.

How to Enable this Feature…
- Sign into the Azure portal as a global administrator or user administrator.
- Browse to Azure Active Directory > User settings > Manage settings for access panel preview features.
Under Users you can use the preview features for registering and managing security info – refresh, you can choose to enable for a Selected group of users or for All users.

For more information click Here.