Make Material Master mandatory in Contract

[charliestephen1]

Hi,

I have a requirement to make entering a Material Master mandatory when creating a material contract (i.e. standard item category). I have followed the path IMG -> Materials Management -> Purchasing -> Contract -> Define Screen Layout at Document Level. From here I went to field selection PT0K (Standard Item Contract) and open Basic Data - but I cannot find the most appropriate field to make mandatory in this section. Can anyone advise which field I should be making mandatory here? See attached screenshot2023-01-24-11-33-41.jpg