Enable read receiptsgmail flag if was opened
gmail read email flag
gmail read email notification
Chrome: Corporate email systems often have ways of telling you if an email is read. For users of Gmail in Chrome, MailTrack creates easy read receipts.
MailTrack, like other read receipt extensions, puts a tiny image in the outgoing email that displays when a recipient opens the email. We've covered apps that do this before, but MailTrack is much easier to use if all you need is a simple notification when someone opens your email.
Note: If the recipient turns off automatic image loading, you won't get a read receipt. What I really like about this free extension is that it not only shows if the email was read, but with which device it was first read on. Just check sent items and a green checkmark will show when an email is read. You can also receive email notifications when the email is read.
If you install the extension, go to the dashboard and remove the signature at the bottom to avoid advertising while you use it.