In the previous recipes, we did user sign-up with a text username and email verification. In this recipe, we will create a user pool to support SMS and MFA verification, and then do sign-up using a login with SMS and MFA verification.
We will also support user sign-up with a phone number as the username. However, you do not need to specify a phone number as the username to support SMS and MFA verification. Instead, you can specify phone_number as an auto-verified attribute, similar to how we specified email in the previous recipes.
