From my perspective, there should be no major roadblocks stopping from building such app type. QR code reader component can read barcodes as well (you’ll need a native app though).
It would be helpful if you could provide more detailed explanation about the problem you’re facing. Some screenshots or short video could help.
Sir i remove the barcode feature i create simple pos client will click the items they want and once they click confirm it will update the remaining stock on inventory can you please guide me. The inventory wont update