That envelope is one you buy yourself...I once bought eBay stickers for shipments, thinking it might help in customs, but never used them.
When you use the international shipping program, you package and print of a label with a mailing address in Kentucky. There is a reference number on the label which gets sorted eventually to the buyer. The nice thing, is that they guarantee the shipping, which means no lost package claims and no negative feedback for anything shipping related, like long delays.