California Code, Elections Code - ELEC § 14216

(a) Any person desiring to vote shall state or provide his or her name and address and, upon the precinct officers finding the name in the roster, the voter shall then sign his or her name in the space provided or, if the voter is unable to sign, shall have his or her name signed by another person on the roster provided for that purpose, whereupon a challenge may be interposed as provided in this article.

(b) The signature shall be capable of being retained for the prescribed retention period for the election being conducted.

(c) This section does not prohibit the use of technology to capture the signature prescribed by subdivision (a).