Cal. Elections Code § 3021.5

(a) Upon the declaration of an out-of-state emergency by the Governor and the issuance of an executive order authorizing an out-of-state emergency worker to cast a ballot outside of their home precinct, a county elections official shall, upon request of an out-of-state emergency worker pursuant to this chapter, issue a vote by mail ballot to the out-of-state emergency worker using a process to be determined by that elections official. The process shall include all of the following: (1) Authorization for a vote by mail ballot and accompanying voting materials to be sent to an out-of-state emergency worker by mail, facsimile transmission, or electronic transmission, as requested by the out-of-state emergency worker. An elections official may use reasonable facsimiles of the county voter information guides sent to voters as vote by mail ballots. (2) A requirement that an out-of-state emergency worker mark the vote by mail ballot provided to them, place it in the vote by mail ballot identification envelope, and return the vote by mail ballot to the elections official from whom it was obtained. If no identification envelope is provided, the envelope used to return the vote by mail ballot to the elections official shall include the information required by subdivision (a) of Section 3011 and a statement signed under penalty of perjury that the voter is an out-of-state emergency worker. (b) In order to be counted, a vote by mail ballot cast pursuant to this section shall be received in compliance with Section 3020. (c) An elections official shall receive and canvass vote by mail ballots cast pursuant to this section by the same procedure as for all other vote by mail ballots cast pursuant to this chapter.