Collect and keep safe evidence proving your position. To file a car insurance claim in California, you must promptly notify your insurer.You must document your expenses and losses to prove your damages. Damages can include monetary and non-monetary losses, like pain and suffering. This guide discusses what to do after an accident and what to expect when you file a claim with your insurance company. To file a car insurance claim in California, policyholders must promptly notify their insurers. Include everything you have. This should include police reports and medical records – anything to validate your claims. If you or a loved one has suffered a personal injury in a car accident, you may be entitled to significant compensation. Compiling all necessary documents related to the accident is crucial when filing an auto insurance and injury claim.