QR-code (or Quick Response code) is a sort of two-dimensional barcode that consists of black squares arranged in a square grid on a white background. QR-code can be read by smartphone camera or specialized devices that are dedicated to QR reading - hand-held scanners, handy terminals, fixed scanners that are used after placing it on a desktop, or embedding it in other devices. Usually QR-codes contain data that points to a website or application, emails, or phone numbers, product identifiers, or trackers.... API usage There are steps that usage...into cloud storage and other files, like digital certificate or...