The Ledger module (also known as general ledger) is where all financial transaction in AX is controlled and stored. All of the other modules are connected to the Ledger module in some way as it is the money central of AX.
The main entity of the Ledger module is the Ledger table that consists of the chart of accounts. In addition, there are transaction tables and other tables related to the Ledger table and, hopefully, you will understand how some of these tables relate to each other by taking a look at the following entity schema from Microsoft:
The following table gives a brief description of each of the tables shown in the Ledger entity schema in the preceding diagram: