iOS >= 11 has a native QR code reader in the camera.
https://support.apple.com/en-us/HT208843
EDIT: 12 -> 11 iOS version correction
https://support.apple.com/en-us/HT208843
EDIT: 12 -> 11 iOS version correction
URLs -> Safari
Locations -> Maps
Contacts -> Contacts
WiFi SSID/password -> Join network