While Wikipedia is not the most reliable source of information, this particular entry is spot on. THIS explains QR codes and what they are.
How do I create a QR code for my event?
It has already been created for you! Under the Promotion tab for your event click on Event QR Code
To save this Event QR Code to your computer, right click and click Save As. This will save the image to your hard drive. Then place this image on your website, and printed advertising materials. When the QR code is scanned by someone with their smartphone, it will take them to your ticket sales page!