The Health Insurance Marketplace is a set of tools and services that aids individuals in the process of searching for, comparing and enrolling in affordable health insurance. The Marketplace also provides information about programs that help individuals of low to moderate income pay for health insurance. The Marketplace run by the federal government can be found at HealthCare.gov. You can also obtain assistance from the Health Insurance Marketplace by calling for assistance or soliciting in-person help.
Based on the information you provide, the Health Insurance Marketplace lets you know what plans you can enroll in and what premium tax credits you might qualify for.
Many states also have marketplaces which they run separate from the federal government Marketplace.