A QR code (Quick Response code) is a type of matrix barcode (or two-dimensional barcode) first designed in 1994 for the automotive industry in Japan. A barcode is a machine-readable optical label that contains information about the item to which it is attached. In practice, QR codes often contain data for a locator, identifier, or tracker that points to a website or application. A QR code uses four standardized encoding modes (numeric, alphanumeric, byte/binary, and kanji) to efficiently store data; extensions may also be used. QR codes are commonly used to store URLs or other information that can be easily scanned by a smartphone or other device with a QR code reader. The 'qrcode' file extension typically indicates an image file (often PNG, JPEG, or SVG) that contains the visual representation of the QR code. These images can be generated by various QR code generators and are used for sharing information quickly and easily.