If a stock category is assigned as a "service", any items that are in this category will not show on a delivery or pick-up slip. See related articles on stock categories.
This is to follow the logic that only a physical item can actually be picked up or delivered and signed for.
For situations where an item that is a service does need to appear on a delivery or pick up slip, there is a feature to override the default setting.
Navigate to the main menu. Select Settings and then System Settings.
In the "Documents" section of settings, toggle on "Show Services on Delivery Slips".
The service items will appear as their own line item.
