What is a UPC code?

The Universal Product Code is a barcode that is widely used worldwide for tracking trade items in stores and online.
UPC (technically refers to UPC-A) consists of 12 digits that are uniquely assigned to each trade item. Along with the related EAN barcode, the UPC is the barcode mainly used for scanning of trade items at the point of sale per GS1 specifications. UPC data structures are a component of GTINs and follow the global GS1 specification, which is based on international standards. But some retailers (clothing, furniture) do not use the GS1 system (rather other barcode symbologies or article number systems). On the other hand, some retailers use the EAN/UPC barcode symbology, but without using a GTIN (for products sold in their own stores only).
UPCs are used to identify products in the music industry, more specifically albums. Anytime you upload a project to Distribution Cloud you are creating a product which is an album. A single song distributed to stores counts as a single song album. Releese can provide you with a UPC code for your album, free of charge.