Basically, QR Codes (Quick Response codes) are similar to classic barcode, but can handle more data. Nowadays they are used everywhere as a handy way to share information, because it is quite fast, can handle thousands of data, easy to generate and easy to read.
Unlike standard bar codes which can handle a maximum of 20 digits, QR Code can handle all types of data – numeric & alphabetic characters, symbols, binary, etc – and more than 4,000 characters can be encoded in one symbol.
How to generate QR Codes? Generating QR Code is very easy. For example, you can use this free online application for creating a simple code. The software program iCandy (for Mac and PC) can create and scan QR codes.
How to read QR Codes? Most of the camera-equipped smart phones have built-in QR Code-reading software, but there are several QR code readers readily available for download.
Following are a few lists: For Nokia Symbian phone, Android, iPhone, Blackberry and Windows mobile. These brief information are collected from internet and I hope this will help you know what QR Codes are.