If you use Shopify as your Store and Shopping cart, it's possible that you're also using Shopify Apps.
One of the popular apps is OneClickUpsell by Zipify Apps (https://zipify.com/category/oneclickupsell/)
OneClickUpsell ( OCU) creates a new Checkout page for you, which will also need to have the Wicked Reports Tracking Code on it.
Luckily, the OneClickUpsell team has made it very easy to add the Wicked Reports Tracking Code to your OneClickUpsell Checkout page.
To setup Tracking on OneClickUpsell, you will follow these steps:
1) From "Settings", Get your Wicked Reports Client Name
2) In your OneClickUpsell Preferences, you will find Wicked Reports.
3) Set the Status to "YES" and paste in your Wicked Reports Client Name
4) Click Save
5) Go to your OneClickUpsell Checkout page (where customer enters email), Right-Click and hit "Inspect" or "Inspect Element" (depending on your browser)
6) Search for "trackfu" in the HTML
7) If you find your tracking code in the HTML, you're done!