For App Store customers, there is no need to enter a license. Please download the app from the app store and it will be licenses automatically.
For iVI Pro 4 customers please visit our website here and click the My Account button on the top right of the screen to log in and view your past orders.
For iVI Pro 3 customers please click here to visit the eSellerate (our license provider) website where you can retrieve your license. You need to either enter your order number or the email address used for the purchase. If you don't have either then please contact our support and we can help further.