ME21N - PO Enhancement using BADI
Hello
As I understand you wish to add a custom tab at header level of ME23N.
Use structure CI_EKKODB in EKKO for adding customer field.
Use structure CI_EKPODB in EKPO in case of item.
Enhance BADI ME_GUI_PO_CUST and add your sub screen using subscribe method.
BADI ME_PROCESS_PO_CUST and set visible /invisible mode of the fields.
Refer this thread too.
Shubham