Hi Ibrahim
By default it is OVERHEAD, when you use it for collecting Overhead expenses
It is INVESTMENT, when you use it for Asset Budgeting purpose or to track expenses for assets constructed In-House (AUC)
If you use it for collecting expenses related to Trade Promotion or Sales Campaign, Use "Profitability"
It will depend on the business purpose you are using the Internal Order.. But by default, it is OVERHEAD
Ajay M