delivery receipt confirms delivery of your email message to the recipient’s mailbox.
But you will not get notification that recipient has seen it or not.
In Outlook, the message recipient can decline to send read receipts.
How to Add and Request Read Receipts and Delivery Notifications?
Track all Messages That you Send:
On the File tab, choose Options > Mail.
Under Tracking, select the Delivery receipt confirming the message was delivered to the recipient’s e-mail server or Read receipt confirming the recipient viewed the message check box.
Track a Single Message:
In the message, on the Options tab, in the Tracking group, select the Request a Delivery Receipt check box or the Request a Read Receipt check box.
Track Receipt Responses:
- Open the original message that you sent with a request for a delivery or read receipt. This message is usually located in the Sent Items folder.
- On the Message tab, in the Show group, choose Tracking.
for more details, visit: office.com/setup.