If you look at any product in your local store, the number underneath the barcode is the product’s GTIN, and this same GTIN is what is encoded in the EAN/UPC barcode. For QR codes powered by GS1 which are intended to be scanned at point of sale, they should have a GTIN in HRI adjacent to the barcode.
When an EAN/UPC barcode and QR code are adjacent on a general retail consumer trade item, HRI for the GTIN is only required for the linear barcode. If the EAN/UPC barcode and 2D barcode are unable to be adjacent, then the GTIN should accompany both.
HRI for any additional consumer engagement (extended packaging) barcode encoding GS1 Digital Link, HRI is left to the discretion of the brand owner.
For further information on HRI, see section 4.14.2 of the GS1 General Specifications.