Mobile app integration for Keyri's QR login system is comprised of installing the Keyri SDKs in the APEX-powered mobile apps as well as creating a getApiCredentials() function for a specific APEX WebSocket API call, examples of which are in the iOS App Integration and Android App Integration pages.
In summary, you simply have to:
The Keyri API includes adaptive UI elements for the confirmation screens, so you don't have to do any design work for your mobile app if you wish not to.