There are specific duties and regulations for every entrepreneur who is dealing with export to countries outside the EU. It is required to follow some rules. Those who export goods to the countries outside the EU (so-called third countries) need to follow the obligations under Act no. 222/2004 Coll. on value-added tax, as amended. The same rules apply to the third countries under the free movement of goods as well.
The taxpayer is obliged to prove the transport of goods to the third country by a document called customs declaration, which confirms the exit of goods from the EU. The paper on the freight of goods is also needed. It can be, for example, a CMR, ship mortgage bond, air waybill, a TIR carnet, or a TR delivery note of the transport of containers.
The place of delivery is defined by § 13.1 letter a) of the VAT Act. The invoice has to be issued within 15 days of the delivery date of the goods or within 15 days after receiving the payment for the delivery.
According to § 47 of the VAT Act, the taxes don't need to be paid in case the supply of goods is dispatched or transported to the third country by the seller or on his behalf.
The taxpayer shall state in the tax return the export of goods in the tax period when the goods were delivered. The delivery day is the day of exit of the goods from the EU territory confirmed by the customs office in the customs declaration.
In the United Kingdom, all the EU legal regulations will be applied until December 31st, 2020. The exact process for exporting goods to the third countries you can find on the website of the Ministry of foreign and European affairs of the Slovak republic.