Short answer: Losing job coverage is a qualifying event, so you typically have a few choices: elect COBRA to keep the same plan, enroll in a spouse’s plan, or buy a marketplace plan during the special enrollment period (where you may qualify for subsidies). Medicaid is also an option if your income qualifies.
When employer coverage ends, you generally have a 60-day special enrollment window on the ACA marketplace plus COBRA rights. Your main options: (1) COBRA; keep your exact plan, but you pay the full premium plus up to 2%; (2) a spouse’s or parent’s plan, if you’re eligible, via their special enrollment; (3) an ACA marketplace plan, where losing job coverage qualifies you for a special enrollment period and you may get premium tax credits based on income; or (4) Medicaid/CHIP if your income is low enough. Compare total cost and provider networks, a subsidized marketplace plan is often cheaper than COBRA.