We can find user exit for any t-code by using the following step’s below.
T-code : SE93
I am using the following t-code as an example ME21N
Press Display button
Note down the package name ,in our example it is ME
T-code : SMOD
Press f4 in the Enhancement field and Input the ME in the package as shown in the figure above and press ok
Now all the User exit related to the t-code will be displayed.You can find user exit for any t-code by following these step’s.