Open the Camera app
Point the camera at the QR code
Wait for the notification to appear
Tap the notification
Follow the link or action that opens
If it does not scan, make sure the QR code is well lit and fully visible
If needed, enable QR scanning in Settings > Camera > Scan QR Codes
Use the Control Center QR code scanner if available on your iPhone
Open the Wallet app to scan QR codes for passes or tickets
Use a third-party QR scanner app if the built-in Camera app does not work