It is recommended that you have more than one multifactor authentication method and to periodically review these methods to ensure they are still relevant. To manage your security info go to the following link: https://mysignins.microsoft.com/security-info or if it is easier to remember use: https://aka.ms/mysecurityinfo
On the security info page, seen below, you can add additional sign-in methods or delete old ones. You can also view your sign-in history or manage your password if you have at least two sign-in methods saved.
To add additional authentication methods click or tap "+ Add sign-in method."" Then select one of the various options from the list.