Email: Why is there a "J" at the End of Some Emails?
The short answer is that the “J” in an email is actually meant to be a smiley face.
This happens a lot if you receive an email from someone who uses Outlook. Outlook uses the Wingdings font to show a smiley face. The letter “J” in ASCII happens to be in the same location as the Wingding smiley, so other email clients simply show it as a “J.”