https://www.ftb.ca.gov/file/when-to-file/extension-to-file.html
Personal
We give you an automatic 6-month extension to file your return. You must file by the deadline to avoid a late filing penalty.
The deadline is October 16, 2023.
An extension to file your tax return is not an extension to pay. Pay the amount you owe by April 18, 2023 to avoid penalties and interest.