Sai,
No way to answer that question without first knowing details of how the existing solution works.
Creation/copy of company code is normally a multifunctional task. SD configuration cannot be done in isolation, you will have to know what your FI, CO, MM, PP, etc etc colleagues are doing.
A generic answer would be that once you know what ALL the business requirements are, you go to Enterprise Structure in configuration and work your way down the list of objects to be copied.
Best Regards,
DB49