Traffic tickets in California are handled by the Superior Court for the county connected with the citation, not by one statewide payment office. Your ticket or court notice should identify the correct court and deadline.
If you want to pay
Use the official county Superior Court traffic page. Paying a citation can close the case and may result in a conviction being reported to DMV, so read the court instructions before submitting payment.
If you want to contest the ticket
California Courts explains that you can request a court trial by the due date. Depending on the court, requests may be available online, by phone or in person. Some courts also participate in MyCitations, including online trial-by-declaration options for eligible citations.
Scam warning
California courts have warned about fraudulent traffic-ticket messages. Use the court identified on your citation or an official California Courts link rather than payment links received unexpectedly by text.