Lawfully present immigrants can get tax credits to help pay premiums and cost-sharing for health insurance through the marketplaces. Like citizens, they can get tax credits to help pay premiums if they make between 100 percent and 400 percent of the federal poverty level. The amount they pay for care will also be lowered if they make between 100 percent and 250 percent of the federal poverty level. To get this help, they cannot be offered affordable health insurance through their job or be eligible for Medicaid.
Lawfully present immigrants who make less than 100 percent of the federal poverty level also can get help paying premiums and cost-sharing if they cannot enroll in Medicaid based on their immigration status. Many lawfully-present immigrants cannot enroll in Medicaid until they have been in the United States for five or more years.
Note that in October 2018, the Trump Administration proposed an expansion to the current policy that determines whether certain immigrants would be considered a “public charge.” While the rule is not finalized, it may eventually impact individuals seeking admission to the U.S. or seeking to adjust status to lawful permanent residence (green card) applying for or using certain public benefits, like Medicaid. Under current and proposed rules, the application and use of premium tax credits and cost-sharing reductions are exempted from the public charge determination test. If the rule is finalized, you will have time to act before the rule goes into effect, and thus can still apply for and use public benefits including Medicaid in the interim.
Undocumented immigrants cannot receive help paying for premiums or cost-sharing for marketplace coverage and may not buy health insurance through the marketplaces even at full cost. (42 U.S.C. § 18071; 26 C.F.R. § 1.36B-2(b); IRS, Affordable Care Act: What You and Your Family Need to Know).