For a license/permit case, a product model is used to represent a specific type of license/permit. Having a specific product model can help support multiple aspects of the permitting process implementation, including but not limited to defining the product, tying together services associated to it, delivering specific product instances, additional workflows, reporting, etc.

Additional fields to describe the permit product can be added if required. For example, for a drivers license, one could add a choice field for license class with choices A, B, or C, then create three records, one per class.

If there are multiple types of permits with unrelated fields, you can extend specific product model classes from the permit model base class. For example, if your agency offers bird taxidermy and wildlife import/export permits out of the same organization, consider whether you need specific permit model classes that would help define different attributes on each permit product.