Law Library -Child Custody
the right and responsibility to make decisions relating to the health, education, and welfare of a child.
Where the child physically lives.
In California, either parent can have custody of the children, or the parents can share custody. The judge makes the final decision about custody and visitation but usually will approve the arrangement (the parenting plan) that both parents agree on. If the parents cannot agree, the judge will make a decision at a court hearing. The judge will usually not make a decision about custody and visitation until after the parents have met with a mediator from Family Court Services.
(excerpted from https://www.courts.ca.gov)