Parent-child access (visitation) is ordered so that the parent who does not have primary custody of the child can still see the child. The court will order reasonable visitation according to the age of the child, but the amount of visitation can vary by agreement between the parents. A judge cannot make a parent visit a child if the parent does not want to.
Source: Superior Court of Arizona, Maricopa County
A parent who does not have physical custody is usually given reasonable visitation time with the children, unless there is some reason it would be detrimental to them.
Source: California Courts.