印信

例句：

1. 1. The official letter was addressed to the president of the company.
   这封官方信函是寄给公司的总裁的。
2. 2. The seal on the envelope is a symbol of trust and reliability.
   信封上的印章是信任和可靠性的象征。
3. 3. The sender's name is written in the upper right corner of the letter.
   信中左上角写有发件人的名字。