A QR Code is a two-dimensional barcode consisting of a black and white pixels which allows to encode up to a few hundred characters. Besides the black and white version, you can also create a colored QR code.
Codewords are 8 bits long and use the Reed–Solomon error correction algorithm with four error correction levels. The higher the error correction level, the less storage capacity. The following table lists the approximate error correction capability at each of the four levels: