When you make a purchase in the xlnaudio.com webshop you do not get a product key. Instead, the product license is automatically added to your XLN Audio user account as soon as the purchase goes through. After that, all you need to do is to run the XLN Online Installer and log-in to your user account and you will be prompted to download/install your registered product(s).
If you purchased XLN Audio products from anywhere else than the xlnaudio.com webshop you will receive a product key with your purchase. You can enter that product key in your XLN Audio user account under Register Product. As soon as the product key has been used to register the product(s) you no longer need it, the license is now registered to your XLN Audio user account.
Examples of XLN Audio product key formats: