71 Pa. Stat. § 733-3
Unless expressly provided otherwise, all written notices required by this act to be given to any corporation or person shall be (1) served in the manner now or hereafter established by law for the service of writs of summons, except that such service need not be made by the sheriff, or (2) mailed charges prepaid, (a) in the case of an individual, to his last known residence or place of business, (b) in the case of an unincorporated association, or a corporation formed under the laws of this Commonwealth, to its principal office, and (c) in the case of a corporation formed under the laws of some other state, to the office of its duly authorized agent in Pennsylvania, or, if there be no duly authorized agent in Pennsylvania, to its home office in the state of incorporation or in any other state.
If a notice is sent by mail, such notice shall be deemed to have been given to the corporation or person addressed when it is deposited in the United States mail for transmission to such corporation or person.
71 P.S. § 733-3