He sent out a bunch of formal invitations, complete with fancy lettering.

他分发了一大堆正式的邀请函，上面配有漂亮的字体。

They haven't said yes and they haven't said no, but they did request a more formal invitation.

朝鲜方面表示很有趣。 朝方并未确定是否参会，但要求给出更正式的邀请。

Are you waiting for a formal invitation?

那你们是在等待一份正式邀请函吗？

He sent out a bunch formal invitations.Complete with fancy lettering.

发了一堆正式请柬 用的还是花体字。

And this is the part where I extend a formal invitation.

而且我现在是正式向你发出邀请。

You've probably seen most of them before, maybe in professional emails or formal invitations, in other types of formal and informal writing.

你可能以前已经看过其中大多数表达了，也许在工作邮件或正式邀请中，在其他形式的正式和非正式写作中。