You can use read receipts to automatically let someone know when you’ve seen their text messages.
When read receipts are turned on, the sender sees the word “Read” below messages they’ve sent to you, indicating that you’ve read their message. If you haven’t read their message, the sender sees “Delivered.”
You can turn on read receipts for everyone or for individual contacts.
Note: To use read receipts, you and your recipient must turn on > Apps > Messages.
Turn off Send Read Receipts.
Note: This action affects only those conversations with contacts whose read receipts you never turned on individually. (See Turn on read receipts for one person, above.