You shouldn't do anything without first speaking to a local personal injury lawyer.
If you had an insurance at the time of the accident, hand it over and let your insurance handle it. Otherwise, seek a legal advice before signing anything.
Sounds like the other passenger is trying to settle her claim with the insurance company for the policy limits. Talk to the insurance company that is handling this case and find out why they want the declaration.
Don't sign anything unless you understand what it means. Talk to a CA injury lawyer.
I am not your lawyer unless we enter into an engagement agreement in writing. This is general information that is given for legal education only. It is not legal advice, and it may not work for your specific situation. I strongly encourage you to consult with a local lawyer to get legal advice and help with your specific situation at your earliest convenience. I am licensed to practice law in Arizona.
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