Cal. Rev. & Tax. Code § 168.1

(a) Notwithstanding subdivision (b) of Section 16.5 of the Government Code, if a county assessor authorizes the submission of a State Board of Equalization form by the use of electronic media pursuant to subdivision (k) of Section 441, a taxpayer may execute that form by electronic signature in lieu of a manual, facsimile, or other signature if both of the following requirements are met:
1. (1) The electronic signature is accompanied by a form in the signature block that states that the taxpayer certifies or declares under penalty of perjury that all the information, including accompanying statements or materials, in the document is true, correct, and complete to the best of the taxpayer’s knowledge.
2. (2) The electronic signature is authenticated in a manner that is approved by the State Board of Equalization.
(b) If a county assessor authorizes the submission of a State Board of Equalization form by the use of electronic media and a taxpayer chooses to execute that form by the use of electronic signature pursuant to subdivision (a), a county assessor shall accept the electronic signature pursuant to this section. The county assessor may require payment of a fee in an amount equal to the reasonable costs associated with accepting an electronic signature.
(c) Every county shall adopt any necessary ordinances, resolutions, or other procedures to give effect to this section.
(d) Upon compliance with this section, the electronic signature shall have the same legal effect as the manual, facsimile, or other signature of the taxpayer.
(e) For purposes of this section, “electronic signature” has the same meaning as that term is defined in subdivision (h) of Section 1633.2 of the Civil Code.