Determining the Transaction Code
You can determine the transaction code for the transaction you want to have recorded in the SAP system.
...
1. From the main menu of the SAP system, choose the application area that the data to be migrated is associated with.
2. Follow the paths until you reach the appropriate transaction.
3.
Choose
System ® Status.
Under the Repository data, you can find the transaction code of the
corresponding transaction.

If you want to know what the transaction code for the Create customer transaction is:
...
1.
Choose Accounting ® Financial accounting ® Customers.
The corresponding dialog box appears.
2.
Choose Master
data ® Create.
The corresponding dialog box appears.
3.
Choose System ® Status.
In the Repository data, you can see that this is Transaction FD01.