2FA is an additional step for logging in that traditionally uses your mobile number or email address.
The popular account security feature 2FA (two-factor authentication) will now only be a part of features offered by Twitter Blue, the paid version of Twitter experience and verification.
2FA is an additional step for logging in that traditionally uses the mobile number or email ID and authenticates a user via a text message or email. The aggressive efforts of Twitter pushing users for the paid version have now risked the security of several accounts, but Twitter cites the reason for shifting this feature as "2FA being used and abused by bad actors".
Twitter will no longer allow accounts to enroll in the text message/SMS method of 2FA unless they are Twitter Blue subscribers. The availability of text message 2FA for Twitter Blue may vary by country and carrier.
Non-Twitter Blue subscribers that are already enrolled will have 30 days to disable this method and enroll in another. After 20 March 2023, Twitter will no longer permit non-Twitter Blue subscribers to use text messages as a 2FA method. At that time, accounts with text message 2FA still enabled will have it disabled. Disabling text message 2FA does not automatically disassociate your phone number from your Twitter account.