Many of us wanna to know or get notification when sent email has been read or how many times has been opened.
The solution is mailtrack.
It’s really easy to get Mailtrack up and running. You just need to do as follows:
1) Open Chrome, go here in the Chrome web store then click Add to Chrome.
2) Accept the permissions.
3) Click Connect with Gmail.
After doing this, Mailtrack should automatically refresh your Gmail. If for some reason, though, you cannot see Mailtrack in your email account, please close then re-open your browser again.
How to Install the Mailtrack Add-on for Android/iOS