ADV
隨本文（或本書）附上;隨信附上
Herewith means with this document, text, or book. You can use herewith in a letter to say that you are enclosing something with it.
例句
...the 236 revolutionary prisoners whose names are listed herewith...
236名革命囚犯，名單附在本材料中
I return herewith your papers.
我隨信退還你的文件。