Item proposal is the list of materials and order quantities that can be copied into the sales order .Item proposal is same as product proposal and SAP uses the two terms interchangeably.“MS” is a standard document type for Product Proposal.A customized document type can be created for item proposal by T-code –VOV8.
VA51 is T-code for creating Item Proposal.This T-code gives a number upon saving,which is linked to the customer data in sales view.