California Code, Public Contract Code - PCC § 1601

(a) Any public entity may adopt methods and procedures to do any of the following:

(b) If a public entity allows or requires bids or supporting materials to be submitted over the Internet pursuant to this section, the public entity shall provide an electronic receipt to the contractor showing the date and time the submission was received.  The public entity shall provide the electronic receipt to the contractor either by immediate transmission to the contractor or by providing the contractor access to an electronic file online that contains this information and that can be viewed and printed by the contractor.