I have answered this in your support ticket. Below is the answer from the communication:
"You can achieve this functionality through the widget template. On the products list widget click on edit and select single items. Select a template and then edit it. On the right you will see a dropdown list for the product types. Select the type for which the custom field is added to. Below the dropdown you will see the insert node. Youd custom field should be located there. Once you click on it it will present the markup needed for it to display. Make sure you add the markup to the <itemTemplate> section of the template in order for it to display."
Ivan D. Dimitrov
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