You would first start by writing your message on a piece of paper, then you would place it into a sealed envelope, and from there, you would go ahead and send it after you put a stamp and address on it.
Primeiro escrevíamos a nossa mensagem  numa folha de papel, depois colocávamos essa folha  num envelope fechado, e, só depois, o enviávamos depois de lhe pormos um selo e o endereço.