Link to an official Lithuanian government source:
https://www.vmi.lt/cms/web/kmdb/konsultacines-medziagos-katalogas/-/asset_publisher/Pec85c90jXW4/content/kurie-pvm-saskaitu-fakturu-rekvizitai-yra-privalomi-/10174
Very important- before ivoice serial number must writen document serie. Example in attached photo (ex.: TCH1 Nr. 30044). serie - TCH1 ; number - Nr. 30044
PVM in Lithuanian - VAT, Sąskaita-faktūra - Invoice