If the users of your mobile website have a need to type in long codes like activation codes, or they like to look up specific products on your website based on a model number printed in a magazine or advertisement, then you too can take advantage of QR codes to eliminate the frustration of tiny keyboards and spare them the need to double check for errors.
But of course, this is just the tip of the iceberg; you can view more use cases.
How to scan QR code on iPhone The QR code scanner app is a built-in feature in the latest iOS devices.