Amazon private label

If anyone who has experience with private labeling products from suppliers in China and selling them on amazon can help me, I would greatly appreciate it!

In order to eventually sell this product on Amazon (will be doing Shopify first), do I need to have UPC’s printed on my product packaging?

Long story short, I know a competitor who has the same supplier as me and I’ve noticed that on their packaging they have upc barcodes printed on them. This competitor also sells on Shopify so I’m curious what the upc codes would be for if/if not used by amazon.

Thanks in advance!