Today, Box customers can only use SMS for their second factor auth. Box is now adding support for TOTP in addition to SMS as the second factor used for authentication. This will provide improved security and flexibility to customers. Any authenticator app that supports TOTP can be used for MFA. This includes Microsoft Authenticator, Google Authenticator, Authy, Duo, etc.
You can find more information here: https://support.box.com/hc/en-us/articles/360043697154-Two-Factor-Authentication-Set-Up-for-Your-Account.