envelope template with international, euro standard sizes c6, c5, c4, c3 for folded a4, a5 paper with cut lines

envelop envelope template a5 dl cut c5 c4 a4 die letter size c6 euro line international mail mockup office post cutout paper empty white blank postal message card isolated vector mock design business open document corporate stationery standard postcard up background object icon print stationary back front identity set frame