The QR code (Quick Response) is a two dimensions bar code that can be quickly read and decoded by a barcode reader, mobile phone, smartphone, or a webcam. It has the advantage that it can store more information than conventional bar code, and especially data directly recognized by applications. QR codes can contain a web address, text, contact details or an event. Using the photo sensor of your mobile phone and a dedicated application, you can scan QR codes and read the information they contain. In the case of a Web address, you can visit the site linked to a card, you can add a person contact details, send a SMS message and many other things. In this tutorial I will show you how to create your own QR code and use it on your Android phone or iPhone.