Short answer
Use an authenticator app when the platform supports it, especially for high-value accounts. SMS can be better than no 2FA, but it is more exposed to number takeover and delivery issues.
What to do next
Use the related resources for the safest next action. Do not paste TOTP secrets, otpauth URIs, QR screenshots, or recovery codes into search boxes, AI chats, screenshots, or third-party support threads.