How auto insurance works in california?

i backed up into a car today and there is no damage to my car but a dent in the others hood, and i said lets call the police and they said lets just exchange information, i said no i'd rather have them come...they said they called when i was getting something in my car and said the police said they would take a while so we decided to exchange info...i got her license but they said they didnt have the insurance info with them....but in the mean time i gave them my info...now i have a feeling that maybe they didnt have insurance and there is no police report so what can happen now?

You are required to exchange contact information. Since there's no damage to your vehicle, and since the other person isn't taking action, they'll probably just have a body shop do the work. If they call you back, ask for an estimate from the body shop before you write a check or refer them to your insurance company.

If they didn't have insurance, they're not going to talk to the police, because car insurance is required to drive in California.

If you want to help them out getting the vehicle fixed, call them up and ask them for an estimate from the body shop. Otherwise, let them come to you.

If you're at fault, their lack of insurance may not absolve you from having to pay the damages.

Just wait, and if anything is brought up, if you decide to settle the issue off the record, get an estimate first!

Was their car parked and/or fully stopped? If in either of those two positions then it wouldn't matter since their car wasn't "moving." If however they where moving then of course legally they should have insurance, and if they don't have insurance, they're not going to pursue you because they'd face ticketing for driving without insurance, and doing so makes them at fault for the accident since a person can't benefit from an illegal action, which driving w/o insurance is.

This depends on what type of insurance you carry and how good your company is. Since your car sustained no visible damage it is really not a big deal for you, however for the other party it could be a problem. Contact your insurance company and make them aware of what happened so that in the event a claim is made against you they are aware of it.
If you posess more than just liability insurance ask your insurance company for a local shop that can examine your bumper for damage. Although the bumper does not appear to be damaged, many bumpers are merely impact foam surrounded by plastic and in such low velocity impacts the foam is damaged but the plastic looks fine. In these instances the next impact will be more severe because your bumper is compromised.