New York operates its own state-based marketplace, NY State of Health, rather than using HealthCare.gov. Residents shop for plans and apply for subsidies directly through the state exchange, which also manages Medicaid and Child Health Plus enrollment.
New York expanded Medicaid under the ACA, so adults earning up to 138% of the federal poverty level generally qualify for Medicaid rather than needing a subsidized marketplace plan. New York also runs the Essential Plan, a low-cost coverage option for residents with incomes a bit above Medicaid eligibility but still relatively modest.
Because New York has this extra Essential Plan tier, residents near the lower end of the income scale should check Essential Plan eligibility before assuming they need a standard marketplace plan, since it often carries very low premiums and out-of-pocket costs. NY State of Health also has its own enrollment calendar and rules that can differ from the federal schedule.