(a) Orders and notices of the commissioner shall be effective only when in writing signed by him or by his authority.
(b) Every such order shall state its effective date, and shall concisely state:
(1) Its intent or purpose;
(2) The grounds on which based; and
(3) The provisions of this title pursuant to which action is taken or proposed to be taken; but failure to so designate a particular provision shall not deprive the commissioner of the right to rely thereon.
(c) Except as may be provided in this title respecting particular procedures, an order or notice may be given by delivery to the person to be ordered or notified or by mailing it, postage prepaid, addressed to him at his principal place of business as last of record in the department. Notice so mailed shall be deemed to have been given when deposited in a letter depository of a United States post office.