In account book setup, you can set value of account book account in your desired level.
Setting account code in Account Book Setup.
To set account code in “Account Book Setup”, click on the “Financial Accounting”, then “Setup”, then click “Account Book Setup”. Account code setup page will be displayed.
Click on “Update” Button on the top of account book setup page. You can set account code in “Account Code” input box against your desired account.
Click “Save” Button to save the information.