In most EU countries, you must provide a proper invoice to Customs to get proof of export, and to the store to get back the VAT.
The following information must be visible on your invoice from the store:
Most stores can provide a proper invoice if you ask for it. Some stores will give you a Tax-Free receipt or Tax-Free form with all the above details included. Tax-Free receipts and Tax-Free forms are valid replacements of a proper invoice and are accepted by all Customs departments in the EU.
If the store can't print a proper invoice and doesn't have Tax-Free receipts or forms, you can download one here. Attach it to your purchase documents from the store when you go to Customs.
Please check our country guide to see the Customs rules per EU country.