show that an email has been opened
In brief, like Outlook is there a option to show when an email has been opened / read by the receiver
Kaikki vastaukset (1)
When composing a message you can ask for a notification to confirm that the message is read by going to Options and checking Return Receipt. In the same menu you can also ask for a Delivery Notification, which is more a technical confirmation that the message is deliverd to the recipient.
Note that either notification won't always be sent. It's up to the recipient or his mail server to send the return receipt or delivery notification.