This is our guide on how to make estimated tax payments to the State of California Franchise Tax Board for individuals.
First, go to the FTB web pay site at:
https://www.ftb.ca.gov/online/WebPay/index.asp for Individuals
You can register for a MyFTB account or you can just enter in your information for the purpose of the current payment.
Once you get in, the top option is Estimated Tax Payment (Form 540-ES)
Then the FTB will ask you to go through the confirming information. Make sure to check if it is a joint or single account.
If your case is in a pending Offer In Compromise, it is highly recommended to make monthly estimated tax payments at least until your settlement is done. This is both for the California FTB and the IRS.