Reading read receipts in iMessage allows the sender of a message to know when a recipient has received it, and the iMessage application for Mac OS and iOS messaging supports this feature when communicating with other iMessage users. But many Mac users do not want to send "visas" around the world, and with the latest versions of Mac OS, you can now selectively choose who to notify of the messages seen. In practice, this is basically the same as turning on the read confirmations for specific contacts on iPhone and iPad, except that it applies to reading and sending iMessages from the Mac message application.
Assuming you have "seen" messages for Mac off, you can adjust these settings in message preferences for individual iMessage accounts.
How to send read receipts to certain contacts in the messages app for Mac
- Open the message application on Mac and then open a conversation with a specific contact you want to send a visa to
- Click the "Details" button in the corner of the message window
- Check the "Send Read Receipts" box to selectively send confirmations to just that specific contact.
- Repeat the process with other message threads and contacts if you wish
Remember, to send read confirmations to specific contacts, you must have this feature off in general terms, and then selectively activate them in some of your contacts.