Two-step verification might be less secure than two-factor authentication, but in adding an extra step to a login process, it does enhance your overall account security. Twitter calls its implementation of 2SV Login Verification in this guide. The guide includes steps for activating login verification via SMS text messaging and via Twitters mobile app for Android. For iOS devices, you will need to flip a Login verification switch to On the Login verification option.”]
Source: https://grahamcluley.com/twitter-login-verification/