A QR codes is two-dimensional code, very much like a barcode, that is designed to be read or scanned by a smartphone. The two-dimensional black and white patterns encode text or other data (for example, a URL link to a web site or a phone number). According to Wikipedia, data storage on a #QRcode is

7089 characters (numeric)

4296 (alphanumeric)

2953 (binary)

(via wikipedia)
Link: QR code data capacity