There are many remote medical billing job opportunities in California. Here are some websites that can help you find such jobs:

1. Indeed.com: This is a popular job search website that aggregates job listings from various sources. You can search for "remote medical billing jobs in California" on Indeed.com to find relevant job listings.
2. Remote.co: This website is dedicated to remote job opportunities. You can search for "medical billing jobs" or "healthcare jobs" to find remote opportunities in California.
3. FlexJobs.com: This is a paid job search website that focuses on remote and flexible job opportunities. You can search for "remote medical billing jobs in California" on FlexJobs.com to find relevant job listings.
4. LinkedIn: LinkedIn is a professional networking website that also has job listings. You can search for "remote medical billing jobs in California" on LinkedIn to find relevant job listings and connect with recruiters.
5. Glassdoor.com: This website allows you to search for job listings, research companies, and read reviews from current and former employees. You can search for "remote medical billing jobs in California" on Glassdoor.com to find relevant job listings and company reviews.

Remember to carefully review each job listing to ensure that it matches your skills and qualifications. Good luck with your job search!