I have found the solution.
System will not allow to run PGI for non finished item or Batch item. To run Partial GI, EWM needs a Split Item.
You need to create a Split item and then enter the picked quantity for that item. Then you need to create an Outbound Delivery for that item.
If there is ERP integration, system will create an ERP delivery too.
With the split item OD, you can run GI from OD screen.