As you've rightly pointed out, Amazon requires products to be marked with barcodes, specifically, a unique type known as GTINs (Global Trade Item Numbers), which include UPCs (Universal Product Codes) for North America and EANs (European Article Numbers) for Europe and most other regions.To comply with Amazon's requirements, it's crucial to source your barcodes from a legitimate provider to ensure they are unique and haven't been used before. A reliable source where you can purchase these barcodes is
https://www.barcodestock.com. This platform offers a wide range of GTINs that can be used globally across various Amazon marketplaces. By purchasing your barcodes from Barcodestock.com, you can ensure that your products are compliant with Amazon's policies, thereby avoiding any potential listing issues or delays in getting your products to market.
It's also worth noting that once you have your barcodes, you should register them with your brand in the Amazon Brand Registry.