Hi Murali,
First, you will write a letter to the ESI director regarding this sub-code. Along with this letter, you must submit:
1. Bank Statement of your Company,
2. If you have any main branch, then that company code (C11) should also be submitted to them or the contract agreement if any,
3. PAN card number,
4. Employee details,
5. Payslips,
6. Main branch last month's challan,
7. Address proof,
8. Concern person's address and contact number who are authorized for that establishment,
9. Letterheads.
I hope these are enough. I received the code by using these documents. Within 7 to 8 days, you will get the code (sub-code). I don't know how many days it will take for the main code.
SRIKANTH