Data Type Enhancements in SAP Process Integration (PI)/Process Orchestration (PO) facilitates modification of input/output data structures of a standard Service Interface or Proxies Interfaces provided with SAP standard applications. Although you can use Data Type Enhancements to append structures to input or output structures of any ABAP proxy (Standard or custom), standard use of the Data Type Enhancements are to add additional data fields to SAP standard ABAP Proxy Interfaces.
Data Type Enhancements Scenario:
Lets assume a scenario where you have a Proxy outbound scenario where you send airline booking information to PI/PO middleware after booking is created in SAP. This Service Interface to send booking information is already provided by SAP, but what if you need to send additional information in the same message? For example a string field with additional notes about the booking.
Editing a standerd SAP object is not allowed in most cases but even if it is allowed, it is not the industry standard best practice. SAP has provided Modification Frameworks or tools to modify standard ABAP objects such as BADIs, DDIC append structures, User Exists etc. Similarly, if you have a requirement to add additional fields to a SAP standard ABAP Proxy Interface’s input or output, you can make use of Data Type Enhancements.