For anyone confused in setting this up, the App is Twilio Authy in the Apple App Store. The logo in the app store has little contrast and the Adafruit blog post just calls it "Authy" which returns dozens of 2FA apps.
> and the Adafruit blog post just calls it "Authy"
Twilio acquired Authy in 2015, but didn't put their brand on it until a year or two ago, so a lot of people just call it "Authy" out of habit/without knowing Twilio owns it.