invitation letter 邀请函；

例句：

Can I look at your invitation letter?

我可以看你的学校邀请函吗？

Here is my passport and invitation letter.

这是我的护照和邀请信。

He receive an invitation letter from the conference.

他接到了大会的邀请信。

I received his invitation letter to the party but I didn't.

我收到了他的聚会邀请信，但是我没接受邀请。

Please take your business card and this invitation letter with you.

届时请携名片并凭邀请函入场。

Make a plan for the day and write an invitation letter to your classmates.

为这一天订个计划并且给你的同学写封邀请信。