SAP has provide various applications to support most of the business process, in case if any of client requirement is not available, we are allowed to modify/enhance the SAP standard.There are many methods of modifying or enhancing the SAP standard and one such way is User Exits.
What are User Exits in ABAP ?
User Exits are the first option available for clients/customers to modify/enhance the SAP standard.As you all know about subroutines in ABAP this concept is also based on it.User Exits are implemented in the form of subroutines. All subroutines which are provided by SAP are empty, you can add code inside it to meet your requirements.All these subroutines are grouped based on their usage in an INCLUDES which are in-turn used in standard programs.
If you look at this option from technical standpoint, it is modification to SAP standard includes to access the subroutines. We need SCCR key to add the code inside the User-Exits.
The basic structure of the User Exit in the includes will look like below.
User Exits are primarily found in Sales and Distribution(SD). You can access them by following this IMG path:
SPRO → SAP Reference IMG →Sales and Distribution → System Modification → User exits.