In SAP ABAP, the debugging facility is not available for Field Exits. SAP suggests we use the 'TRANSFER' command
to write the values during runtime, but the downside is that we have to go to the Apps server every time we want to display this data. An alternate solution is to set the values in global memory by using 'SET PARAMETER' and then go into debugging mode for that particular screen. After the Field command in the Flow Logic, this global memory will be filled with the runtime value. In debugging mode, use the following path to display the value in global memory: Goto --> System --> System area, type SMEM on the Area screen field followed by enter and now you can see all the global memory values.