Packing material will appear in invoice or not

Hi Friends,

In delivery there are 2 materials one is main material and other one is packing material.

Main material is relevant for Billing if you see in the item category and the Packing material is not relevant for billing.Whether because of this Packing material will appear in the billing document or not.

Packing Material is there only in the delivery so whether we have to check the item category VOV7 or 0VLP for the material to appear in the billing document.

If the Packing material is not appearing in the invoice what will be the reason ?