It's really easy to get Mailtrack for Gmail 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 Mailtrack for mobile
Mailtrack is the only email tracking system that integrates with Gmail’s official app. Not only that but the tool is available as a free download and comes with no tracking limitations for users. This is how to install it on your iPhone or Android.
How to install Mailtrack for Outlook or other email clients
Although Mailtrack does not offer compatible add-ons for Outlook or other email clients, it is possible to route your email provider through the Gmail app. Once you've done it, you'll be able to use Mailtrack to track email opens in Outlook, just like other Gmail users do.