A QR code, short for Quick Response code, is a two-dimensional matrix barcode that stores information in a pattern of black and white squares. It can encode various types of data, such as URLs, text, contact information, or product details. Users can scan QR codes using a smartphone or QR code scanner, which quickly deciphers the pattern and reveals the embedded information. QR codes are widely used for efficient data sharing, marketing, payment transactions, and authentication due to their quick readability and versatility.