scribe; amanuensis; professional letter writer
A person who writes documents on behalf of others, especially in historical or formal contexts. In modern Japan, this role is largely obsolete, but the term may appear in historical or legal settings.
In the Edo period, scribes wrote letters on behalf of others.
He works as a scribe near the government office.
Compound of 代 (substitute) + 書 (write) + 人 (person). The term directly describes a person who writes in place of another.