TOTP Authenticator generates 6-digit TOTP codes. Websites (for example Arbeitsagentur, NextCloud etc.) request these codes. This security feature is called two factor authentication or 2FA.

How to sign in using TOTP?
1. Go to the “Security” section
2. Enable TOTP login
3. Scan the QR code or copy the secret key into your Authenticator
4. Done — 2FA is now enabled. From now on, you’ll need to enter a TOTP code from the Authenticator app whenever you log in

The app also includes over 100 step-by-step tutorials with screenshots showing how to set up TOTP for various websites.