Answer:
Make sure attribution models account for cross-device conversion
Step-by-step explanation:
Since in the question it is mentioned that Jenni sold customized printed t-shirts also the customer starts their journey online by researching the mobile devices and the purchase could end up with desktop usage.
But in the current status, mobile is unable to get any credit so to solve this problem make a model account for the conversion of cross device that means if any user clicks on one device that the result should be shown on the other device