You can generate free QR codes on this website. A QR code is a two dimensional barcode that stores information in black and white dots (called data pixels or “QR code modules”). Besides the black and white version, you can also create a colored QR code. For these codes to work without problems, make sure the contrast is sufficient and the result is not a negative (in terms of color). To make your QR code even better, you can also get a QR code with logo.