User exit is a classic concept. User exit is a blank code block in the form of subroutine which lies in a standard program (perform-endform). Now to write our own piece of code we shall need access key for the standard program. Modifying standard program will not be a good idea because SAP will not provide any support if any bugs are found.
From ECC 6 onwards SAP has implemented enhancement point, the implicit enhancement. By using implicit enhancement we can write our own code into a coding block. We can write our own code into a standard program or any function module or any include program also. The code block will be under a subroutine (perform – endform). Now our piece of code will be under Enhancement – Endenhancement block which is under that perform.
The enhancement must be created under a package & transport request. Any local object will not be accepted here because SAP system wants to take the versions of this enhancement.
With implicit enhancement we can create our custom code into a function module, include or standard program where the ENHANCE (coin) button exits. Now in the following example we have discussed a step by step approach to make an implicit enhancement. Here we have taken a standard include program of order. We have a format of standard include programs.