There are lots of free QR code apps to download, including CliqTags QR Code Reader, but in iOS 11 the camera app will be able to read QR codes directly from any photo.
9to5Mac – Top 10 QR codes supported by iOS 11 (including CliqTags links of course)
This is very good news for the proliferation and ubiquity of QR codes, and we of course applaud this initiative. Long overdue, but nevertheless excellent.
If you don’t know how to set this up in Android, here are pointers: phoneArena – How to scan QR codes and regular barcodes using just your camera app and Now on Tap (Android)