Log Every Email to Daily Files With Rotation
Writes one line per outgoing email (time, recipient, subject, result) to a daily log file in a protected uploads folder, and deletes files older than the number of days you choose.
Snippet Library
Email snippets for WordPress
Snippets for the emails WordPress sends: change the sender name and address, add a Reply-To header, send HTML email and turn off notifications you do not need. For site owners who want their messages to arrive and look right.