The chart from the Internal Revenue Service (IRS) below explains how the Affordable Care Act (ACA) affects your tax return and what you will need to do when filing.

IF YOU… THEN YOU…
Had health care coverage for the entire year for yourself and everyone in your tax household Will simply check the box on your individual income tax return on the line labeled “Health care, individual responsibility” to indicate full year coverage.
Enrolled in health insurance through the Marketplace Should receive a Form 1095-A Health Insurance Marketplace Statement from the Marketplace.
Enrolled in health coverage through the individual market or a government sponsored plan Should receive a Form 1095-B, Health Coverage form from the provider.
Worked for an applicable large employer (in general, an ALE is an employer with 50 or more full-time and full-time equivalent employees) May receive a Form 1095-C, Employer-Provided Health Insurance Offer and Coverage Insurance, from your employer.
Received a Form 1095-C, Employer-Provided Health Insurance Offer and Coverage Insurance, from your employer reflecting coverage your employer offered, even if you chose not to take that coverage Will use Form 1095-C to determine your eligibility for the premium tax credit if you enrolled in coverage through the Marketplace. If you or any family members enrolled in self-insured employer coverage, you may receive Form 1095-C showing this coverage.
Received a Form 1095-B, Health Coverage, from your coverage provider showing you or any family members had health coverage Will check the full-year coverage box on your tax return, if Form 1095-B shows coverage for you and everyone in your family for the entire year.

If there are months when you or your family members did not have coverage, determine if you qualify for an exemption.

Received a Form 1095-A, Health Insurance Marketplace Statement, showing you received the benefit of advance payments of the premium tax credit Must file a tax return and reconcile the advance payments with the amount of the premium tax credit allowed on your return.
Received a Form 1095-A, Health Insurance Marketplace Statement and did not receive advance payments of the credit. Will use the form to determine if you are eligible for the premium tax credit. Check the full-year coverage box on your tax return, if the form shows coverage for you and everyone in your family for the entire year.
Need to reconcile advance payments of the premium tax credit with the credit allowed Must file a tax return and IRS Form 8962 Premium Tax Credit (PTC) to reconcile.
Must repay excess advance payments of the premium tax credit (you will determine this using Form 8962, Premium Tax Credit (PTC)) Must report the information on Form 1040 or Form1040-A on the line labelled “Excess advance premium tax credit repayment.” You cannot file Form 1040-EZ.
Are claiming the premium tax credit and did not benefit from advance payments of the premium tax credit Must file a tax return and IRS Form 8962, Premium Tax Credit (PTC) and claim the credit on the line labelled – Net premium tax credit.
Did not receive an expected Form 1095-A, 1095-B or 1095-C regarding your health coverage Should contact the entity that is supposed to issue the form.

Chart source: https://www.irs.gov/affordable-care-act/individuals-and-families/health-care-law-and-your-tax-return