A key aspect of the Affordable Care Act was to establish a marketplace known as exchanges for the purchase of health insurance. A report from the Congressional Research Service (CRS) provides an overview of the various components of exchanges, how they are structured, intended consumers, and available assistance. The report also provides a brief summary of the implementation and operation of exchanges since 2014.
The report can be accessed at http://fas.org/sgp/crs/misc/R44065.pdf.