If you’re using an iOS device, just open the camera app and hold it over a QR Code until a notification pops up. Same for Android or other mobile devices, except that if nothing happened, you may want to check your settings and see if QR Code scanning is enabled. Otherwise, search for a reliable QR Code reader in your app store, most of them are free!
We also have our own free QR scanner to see what info a QR code contains. You can use it by simple upload a QR code and we will show you the content of the QR code. Use our Free QR reader here.