California Code, Elections Code - ELEC § 3001

(a) Except as provided in Chapter 3 (commencing with Section 3200) and Sections 3007.5, 3007.7, and 3007.8, application for a vote by mail voter's ballot shall be made in writing to the elections official having jurisdiction over the election between the 29th and the 7th day prior to the election. The application shall be signed by the applicant and shall show the applicant's place of residence. Any applications received by the elections official prior to the 29th day shall be kept and processed during the application period.

(b) No later than 29 days before the day of the election, the county elections official shall begin mailing the materials required by Section 3010 to qualified applicants for vote by mail ballots, including voters who are permanent vote by mail voters pursuant to Chapter 3 (commencing with Section 3200). The county elections official shall have five days to mail a ballot to each person who has requested a vote by mail ballot by the 29th day before the day of the election and five days for each voter who requests a vote by mail ballot after that date. The county elections official shall not discriminate against any region or precinct in the county in choosing which ballots to mail first within the prescribed five-day mailing period.