QR codes consist of a pattern of black and white squares arranged on a white background. The squares are arranged in a grid, and each square can be either black or white. The pattern is read by a QR code reader, which can be a smartphone app or a dedicated QR code scanner.

QR codes can store a large amount of data, much more than traditional barcodes. This is because they can store data both horizontally and vertically, while traditional barcodes only store data horizontally. This means that QR codes can store URLs, product details, contact information, and much more.

To use a QR code, you need a smartphone or a QR code reader. You simply open the app, point your phone's camera at the QR code, and the app will decode the pattern and display the information stored within the code. This can be a website URL, a phone number, or any other type of data.

QR codes have become increasingly popular in advertising, marketing, and product labeling due to their ease of use and ability to store large amounts of data. They can be used on posters, billboards, product packaging, and even on TV commercials. QR codes are also used in ticketing, payments, and loyalty programs.

In addition to the standard QR code, there are also several variations, including Micro QR codes, which are smaller and can store less data, and Frame QR codes, which can include an image or logo in the center of the code. Overall, QR codes have become an important part of modern technology and are likely to continue to be used in a variety of applications in the future.