Most individual and family plans available through the ACA Marketplace are HMO-style plans. This means you’ll typically need to use in-network doctors and hospitals, and get a referral to see a specialist. PPOs, which offer more flexibility, are rarely available in the individual market. All ACA-compliant plans are required to cover essential health benefits, including preventive care, prescription drugs, emergency services, mental health, maternity, and more — but networks and plan details vary by carrier.