Importance to add document type in P40040 for distribution

Hi,

We are moving from 8.0 to 9.1., tool 9.1.2

I want to know if we need to set up the document type in P40040 application for Inventory/Procurement module, I know it is important to set up for maintenance module but not sure if we need to set up for Inv./procurement . We are using maintenance module. Just to let you know we are not using following.

 

·         Advance stock valuation.

·         Cross docking workbench

·         Lot location tracking.

·         We are not using sales modules

 

I have looked into following document.

E1: 40: Document Type Master (F40039) in Distribution and Manufacturing (P40040) [ID 1367578.1]

 

Do we still need to add the document type in P40040, if yes then what are the document types required to be added, what is the criteria to set up document type? Example: Commit Procurement Orders 40/CT what it will do if we add in P40040?