A frequent recipient of my e-mails is being required to send a receipt showing that she received the e-mails. How do I undo this requirement?
What email client/app are you using? Is there a SETTINGS item for DELIVERY RECEIPT REQUEST or READ REQUEST activated?
FWIW, the following post describes a similar issue:
Random read receipt requests when sending email via Comcast webmail 02-13-2020
Issue: Editing a draft email (even if it is only in order to send it) triggers the addition of a read receipt request.
Workaround: If you have edited a draft email (from your "Drafts" folder), don't send the email from that window. Instead, create a new compose window, copy the addresses, subject, and text of the email from the draft window to the new compose window and send it from there.