Native QR code scanning has been built into phone cameras since Android 8 and iOS 11 (both from 2017), so you’re not going to have any problem reading a QR code on a modern smartphone — no ...

A bug in the QR code reading function of "iOS 11" standard camera application, it is possible to set the URL displayed and the linked website different from each other ...

The city of Denver told the Problem Solvers that “the PayByPhone branded QR Code does not direct them to a website, either our own, or a third-party website.“ Users may see ads on the app.