California Code, Corporations Code - CORP § 8

Writing includes any form of recorded message capable of comprehension by ordinary visual means; and when used to describe communications between a corporation, partnership, or limited liability company and its shareholders, members, partners, directors, or managers, writing shall include electronic transmissions by and to a corporation (Sections 20 and 21), electronic transmissions by and to a partnership (Section 16101), and electronic transmissions by and to a limited liability company (paragraphs (1) and (2) of subdivision (o) of Section 17001). Whenever any notice, report, statement, or record is required or authorized by this code, it shall be made in writing in the English language.

Wherever any notice or other communication is required by this code to be mailed by registered mail by or to any person or corporation, the mailing of such notice or other communication by certified mail shall be deemed to be a sufficient compliance with the requirements of law.