It is a two- dimensional code like a matrix code which contains data in both directions: horizontal and vertical.
It consists of black modules arranged in a square grid on a white background, which can be easily read by imaging devices such as cameras on mobile phones with QR Code reader applications (apps).
QR codes are quite handy and has multiple uses in sales and marketing activities.
When designing consumer promotions or for consumer engagement, you could print the QR codes on the packaging and integrate it with apps, leading the consumer to its website or social media pages. You could even make the QR code trigger other applications or games or any form of entertainment which the consumer will associate positively with the brand.