Create Custom Logic Using Key User Extensibility and Perform Trace

[JHFVR]

Tutorials: https://developers.sap.com/tutorials/abap-s4hcloud-procurement-po-customlogic-tracing.html

The BAdi link under "more information" way at the end leads to a documentation for a release no longer under maintenance: https://help.sap.com/docs/ABAP_PLATFORM_2021/46a2cfc13d25463b8b9a3d2a3c3ba0d9/8ff2e540f8648431e10000000a1550b0.html?locale=en-US