I'll send the original to you by post.

我将把原件邮寄给你。

《牛津词典》

The vase was quite fragile so we had to wrap it in soft material before we send it by post.

这个花瓶很易碎，所以我们在邮寄前必须用软材料把它包起来。

youdao

Do not send them your application by fax, for instance, if companies ask for it by post.

比如，如果公司要求邮寄申请书，就不要把申请书通过传真机传输给他们。

youdao

He will send it to you by separate post (invoice enclosed) and was delighted to know you are also a lover of Charles Lamb.

NPR: Part One

It uses the post office to send clothes by air to the farthest-flung corners of the vast, icy, sparsely populated country.

ECONOMIST: Selling clothes online in Russia

Another fifth send money orders via the post office and receive their order by return mail.

ECONOMIST: Selling books in China