I want to send this letter special delivery.

这封信我想寄限时专送。

youdao

I want to send this letter on special delivery.

我想特快专递这封信。

youdao

Send this letter to Beijing by special delivery.

快件寄这封信到北京。

youdao

Send this letter to Beijing by special delivery.

快件寄这封信到北京。

youdao