This plugin collects information when a page receives utm parameters.
When a page is accessed and if at least one utm parameter is passed (e.g. utm_source, utm_medium)
that info will be saved in a session along with some more info.
Later when the user fills out any form that uses wp_mail function
the collected utm data will be appended to the email's content.
The main benefit is that you'll know where the user came from and which pages he/she visited
before filling out the form.
Note: If, after the purchase, you don't get the download email go to Support > Download Purchased Product