Cal. Rev. & Tax. Code § 42103.2

Every seller, except a seller that is not required to collect the local charges pursuant to Section 42101.7, shall register with the department. Nothing in this section prevents a seller from registering with the department on a voluntary basis to collect and remit the charges even if the seller meets the de minimis sales threshold provided by Section 42101.7. The department shall establish a method for registration of sellers under this part that uses the existing registration process for a seller’s permit established pursuant to Section 6066 of the Sales and Use Tax Law (Part 1 (commencing with Section 6001)). Every application for registration shall be made upon a form prescribed by the department and shall set forth the name under which the applicant transacts or intends to transact business, the location of its place or places of business, and any other information that the department may require. An application for registration shall be authenticated in a form or pursuant to methods as may be prescribed by the department.