All you need to do is open your camera and point it at the code. It will take you to the site.
I only know this because school sent home two pages of codes for learning songs for dc. I was downloading all the different QR code apps go find there were hidden costs!
A quick google showed me that I didn’t need a separate app, thank god!
So for those who have an iPhone (not sure about android, sorry), just open your camera. Don’t worry about a fancy app