See: How Long Can You Stay on Your Parent’s Health Insurance?
To comply with the Affordable Care Act (ACA), all health insurance companies in states where coverage is available must let a child stay on their parent's plan until age 26. However, some young adults can stay covered by their parent's health insurance thanks to "riders." After the age of 26, various health insurance options are accessible to you, including those provided by employers, those purchased through insurance exchanges, and government-funded programs like Medicaid.