QR code (Quick Response Code) is two dimensional barcode or a matrix barcode that readable by smartphone Android or IOS. It encodes 4000 characters into two dimensional barcode.
A QR code consists of black square boxes arranged in a square grid on a white background, which is readable by smartphones or other imaging devices such as camera.
For reading the QR Code with your smartphone, you need to install an appropriate application on your phone. The android phone user use Barcode Scanner and IOS use Nigma it's available in AppStore.