The QR, Barcode Scanner for iPhone lets you use your iPhone camera to automatically scan and recognize many types of QR code or barcode data, supports all major code formats, and includes a 2FA ...

Do I need to use a third-party app to scan a QR code? Our reader above asked us to recommend QR code reader apps. However, I recommend not using these reader apps at all.

Now when you click Camera Control, the QR code scanner app will be instantly invoked. You'll also see that there's a Magnifier option that you can assign to the button from this settings menu.