All Greenlight customers use their phone number and password to log into the Greenlight. However, Greenlight offers a 2nd verification option using biometrics. Opting into this additional security setting will prompt TouchID or FaceID each time you try to open the app. To enable this feature, head to your Settings tab in the Greenlight app.
Please note: right now this enhanced login is only enabled for iOS users, but this is coming soon to Android!