Bitcoin QR code on a product sold in stores How and which company do i turn to implement a QR code for bitcoin on a product sold within stores.
Putting a bitcoin payment address (in QR code format, or otherwise) is generally not the way to accept bitcoin for a sale. There would be very basic vulnerabilities, such as having someone swap the payment address displayed on your product, etc. Attempting to use the same address on every product is bad for privacy/fungibility, and it makes backend accounting difficult. 

Accepting Bitcoin for payments is best done using a bitcoin payment processor such as BTCPayServer (an open source project), or for small scale you could even process payments manually at the till. In either case, customers would be presented with a payment address during checkout, not a payment address per product.