At the moment of purchase, request for a Customs Tax Invoice from a store employee. Please note that only shops with a licence to sell to military staff are able to provide you with this type of invoice. Your station can provide you a list of licensed shops. Furthermore, only items with a minimum purchase amount of €46 (including VAT) can be listed on the CTI for a VAT refund.
After visiting the store go to your NATO base administration office to get a stamp on the Customs Tax Invoice for approval
(*) Please make sure to upload a copy of the front and back of your NATO ID
(**) When registering your receipt under the receipt page, make sure to upload the copy/scan of your receipt AND Customs Tax Invoice