A QR code is a square, two-dimensional barcode that can store information. QR stands for Quick Response. A phone camera or scanner app can read the pattern and turn it into a link, text, contact card, Wi-Fi login, payment instruction, ticket, or other data.
Unlike a simple one-dimensional barcode on a product package, a QR code stores information both horizontally and vertically. That lets it hold more data in a small space. The three large corner squares help the scanner understand the code's position, so it can read the pattern even if the code is tilted.
QR codes are popular because they connect physical objects to digital actions. A restaurant can place a QR code on a table for a menu. A museum can link visitors to audio information. A product box can link to setup instructions. A ticket can use a QR code for entry.
QR codes should still be used carefully. A printed code can hide the actual link until after scanning. A malicious code could send someone to a fake login page or unsafe download. It is smart to check the previewed address before opening a link, especially in public places.
The simplest definition is this: a QR code is a machine-readable square that stores data. Its value comes from making information easy to open quickly with a camera.