Envato Elements does not issue purchase codes when you download an item, instead, you get an ongoing license for a single, specified use once you register the item for a project. The licenses you get for items you download and register from Envato Elements are only valid if you complete your End Products while your subscription is active. Then the license continues for the life of the End Products (even if your subscription ends).
For audio items, you are provided with a license certificate which can be accessed when downloading and registering the item and also via the ‘My downloads’ page.
Learn more about the nuts and bolts of the Envato Elements License here.