Citation, Documentation of Sources

Q. What is the proper way to reference an email in a report?

A. To cite any form of personal correspondence, give the person’s name, the medium of the correspondence (letter, fax, email), and the date. For the sake of privacy, do not cite the sender’s address (home or email). See CMOS 14.214 and 15.53.

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]