how to make item field mandatory based on line type

Summary:

Hi All,

We have a requirement to make the item field mandatory only when the line type is "Goods". For all other line types, the item field should remain non-mandatory. 

When creating a requisition amount based, the item field is expected to have some input in the background, but it is not visible on the screen. Therefore, we need to make the item field mandatory only for the "Goods" line type. Can you please guide us on how to achieve this, and what conditions should be added at the detail level? 

Additionally, we need to make the "Shipping Method", "Freight Terms", and "Pick up Location" fields non-mandatory for a specific document style.