To register to vote in California, you must be:
Military and Overseas Voter Registration
Confidential Voter Registration
Conditional Voter Registration
Currently serving a state or federal prison term for the conviction of a felony in:
* California Penal Code section 2910 allows the California Department of Corrections and Rehabilitation (CDCR) to make agreements with local governments to house felons in a county jail or other correctional facility. A person serving a state prison sentence who is housed in a local jail or other facility under these circumstances is not allowed to register to vote.
Voting Rights: Persons with a Criminal History | California Secretary of State
Proposition 17 removed being on parole for the conviction of a felony as a disqualifying factor to register to vote. If you are on parole for the conviction of a felony you can register to vote.