The society shall have corporate existence as a domestic stock or mutual life insurer upon issuance of the certificate of incorporation by the commissioner or approval of the amended articles of incorporation, as the case may be; but it shall not transact business as an insurer until all its authorized capital stock, if a stock insurer, has been subscribed and paid in full and it has otherwise qualified for, and received from the commissioner, a certificate of authority as provided in this title for legal reserve insurers.