The principal place of business is could be any of the places of business of a person, which is located in the same State in which the registration is intended to be obtained. Generally, this location would be the head office or the corporate office or the billing address of the person, or the address registered under a statute such as the Companies Act, or as specified in the partnership deed. Once a location is chosen, it would be used for correspondences by the GST officers, and should therefore be mentioned on the certificate of registration.
The law requires that the books of account shall be maintained at the principal place of business, or may be maintained electronically, on fulfilling the conditions prescribed by the rules.