The QR code is a kind of barcode label which has machine-readable information. You can download and print their biometric data with the QR code from the UIDAI website or its mobile app.
It is basically the barcode that now comes with photo, can be used in offline mode. Unique Identification Authority of India (UIDAI) has introduced this updated QR code that holds details like name, address, photo, and date of birth, and can be used for offline user verification without the 12-digit ID number.
For an example, when you ordered something online and after a few days the shopping delivery guy comes to deliver your product and asks for ID, you can show him the printed QR code which when scanned shows your name, address, date of birth and photo, thus establishing the authentic identity.