3524104 - How and Why an approver who actually approved the document is determined.

There is no record in the purchase order or any other document indicating that it was approved by a substitute.

SAP S/4HANA Cloud Public Edition

Currently no display of who actually approved, that is substitutes who have approved it in approval details tab of any document.

Steps to see the substitute details of any document is given below:

1. Open APP "Flexible workflow administration".
2. Select the respective Work item and then click on 'log details'.
3. Here, the user who approved as a substitute can be seen.

 Example message "User CB000000001 as the substitute for CB00000002 has become the processor of work item 000000XXXX" 

1.Refer to SAP Note 2490102 - Substitute approver for purchase orders - SAP for Me

2.Also found below Idea in customer influence forum that is related to supplier invoice,

Comments can be added to include PO and other documents 

Improvement Request Details - Customer Influence (sap.com)

SAP S/4HANA Cloud Public Edition, Sourcing and Procurement, Operational Procurement, Purchase Order Processing, Manage my substitutes, Substitute Approval, Purchase Order, Workflow Administration,Actuall approver, Who approved. , KBA , MM-FIO-PUR-PO-WFL , Purchase Order Workflow , Problem

SAP S/4HANA Cloud Public Edition all versions ; SAP S/4HANA Cloud all versions