2FA is a security feature that enables two steps of user identity authentication for Insightful login.
First and basic one is with user credentials:
Unique password created by user
Enabling 2FA, Insightful will ask for another sign in step for verifying the identity of the user trying to sign / log in with help of time-based security token generated by third party authenticator apps.
To get the token open your Authenticator app, locate Insightful account you previously set up read and type the code into Security Code field
To learn how to set up 2FA, read this article.