IMG -> Enterprise Structure -> Definition -> Financial Accounting -> Define, Copy, Delete, Check Company Code
Please double click on Edit Company Code
By selecting the second option edit company code data you have to manually configure all the subsequent assignments.
By selecting the first option all the configuration and tables get copied automatically along with assignments. This option should be selected in case of rollouts.
In the copy option you need to click on the copy icon to copy a company code from an existing copany code. You can copy from existing company code delivered by SAP.
You can select a four-character alpha-numeric key as the company code key. This key identifies the company code and must be entered when posting business transactions or creating company code-specific master data, for examples.