1) QR codes can contain various amounts of data depending on whether they are 1D or 2D barcodes. 2D QR codes can hold the most data at up to 7,089 characters.
2) There are many free QR code scanner apps and some devices have scanners built-in. The amount of data and precision needed increases with more complex QR codes.
3) QR codes can link to various types of content like websites, phone numbers, or app stores and can be used on both printed and digital materials to bridge the physical and online worlds.