The document provides an overview of QR codes, which are standardized tags storing data in a pixel grid, often used for tracking products and in promotional campaigns. Created in 1994 by Denso Wave for vehicle tracking, QR codes can store more information than traditional barcodes and are now utilized for various purposes including app downloads, online verification, and even on tombstones. Since their introduction in smartphones in 2002, QR codes have evolved, incorporating features for branding and security.