letter的complimentary close後要留多少行俾手寫簽名?

4行。

Allow four spaces between the complimentary close and the typed version of the writer's full name. The space between is reserved for a handwritten signature. The writer's job position or title should appear directly below his or her name.

(from:http://edu-net.net/bus-writing/writing/guides/documents/business_writing/business_letter_format/complimentaryclose-2.html )