Why, the mark of the beast, of course!Â  HA, I KID.Â  The UPC/EAN is a numerical code, usually associated with a barcode, that uniquely identifies your product for sale.Â  You need to buy one, usually, for a nominal fee.Â  Sometimes your label has â€em.Â  Sometimes you can get them from your distributor (Tunecore and ReverbNation will allow you to get a UPC for your release).Â  If you want to sell your music in stores, physical or virtual, you need a UPC.Â  The UPC code also can (and should) be embedded in the CD metadata itself.