adverb
herewith
heer-WITH/ˌhɪrˈwɪð/
Together with this document, statement, or action.
The messenger submits the sealed statement and the parcel attached herewith.

Etymology
Here points to the present document or statement rather than a physical place. With developed a sense of association, giving the compound its meaning of something accompanying this document or statement.
In context
"The Left Hand of Darkness" is returned herewith.
I've kept half of it and am herewith sending you the rest.
More examples
- The documents submitted herewith support the application.
- I send herewith the requested copy.
- The report presented herewith summarizes the findings.
Forms
herewith
Similar words
- hereby
- Hereby means by this action; herewith means accompanying this document or action.