Scanner identifies few small squares codes within a big single square code. Quick Response codes or QR codes 2d types of barcodes that are used for transmitting data from square code while scan. QR codes are automatically generated as black squares and white squares on generating it which detects the data by scanner.
Each of these squares in QR is called a module and module shall not be changed or edited once it is generated and this is just to avoid 'no result' while product scan. QR code will be mostly square symbol, and scanner understand the minimized data to a larger one. There are few QR code generators available online and you can create QR code through it.
General info: Quick Response codes or QR code is a trademark of Toyota Japan, QR's main invention was to track car parts inventory. QR codes are available online as free which can create and use it as per convenient.