MMBE is a transaction, not a table. It refers to SAP standard report RMMMBESTN.
There are several steps to take in order to add a field to the report:
- Does the field that you want currently exist in a SAP table? If yes: go to step 3
- If no: You have to add the field to APPEND structure of the appropriate SAP table in SE11. In this case you have to also consider how this data is going to get into the table in the first place, who's going to maintain it etc. (I'm not going into that)
- If yes: You have to enhance report RMMMBESTN. In a ECC6 System you can use any of the enhancement Spots supplied. In earlier systems you may have to repair the program.
DO NOT copy transaction MMBE to ZMMBE and then change the program. When you upgrade the SAP standard program may change. If you repair a program or use enhancement spots SAP Modification assistant will help you to apply your changes to the new program - otherwise you're on your own.