Federal law says states must cover some people like families with low income, pregnant women, kids who meet certain rules, and people who get SSI (Social Security). States have more ways to cover people and can choose to cover people who wouldn't be qualified otherwise, like people who get services at home or in the community or kids in foster care.
The Affordable Care Act helps states cover people who are under 65 and don't have much money. Most states have decided to include adults in their coverage, and those that haven't can do so at any time. Check to see if your state has added low-income people to Medicaid.