As part of the two-factor authentication process, Twitter announced today that you can now use a USB security key, such as Yubikey. In an effort to improve security it is the latest expansion of Twitter’s verification support, which, as of last year, also includes third-party apps like Google Authenticator and Duo Mobile. You will be able to sign in securely even in situations where you can’t or don’t want to have a text message sent to your phone by using this physical key. This security measure has already been added to Google, Dropbox, and Facebook already.
— Twitter Safety (@TwitterSafety) June 26, 2018
You can see how to set up your Twitter account for security key verification here.