On Amazon, product codes are usually obtained in the following ways:

1.UPC (Universal Product Code): You can buy it from formal organizations such as GS1.

2.EAN (European Article Number): It is also obtained through the relevant coding management agency.

3.ISBN (International Standard Book Number): Applicable to books, which can be obtained from the corresponding management organization.

4.ASIN (Amazon Standard Identification Number): This is a unique code assigned by Amazon to products sold on its platform. When you successfully create a product listing on Amazon, Amazon will automatically generate an ASIN for your product.

It should be noted that using legal and compliant product codes is very important for your sales activities on Amazon.