If you obtain your health insurance through a Federal or State Healthcare Marketplace (Exchange) you may be receiving premium credits lowering your monthly cost for health insurance premiums.
On your tax return, you are required to file forms that reconcile the amount of credit you received with the amount you were actually eligible to receive based on your income level. This reconciliation is based on Form 1095-A which was mailed to you in January. Failure to include Form 1095-A on your tax return will delay processing of the return and any potential refund.
Beginning with the 2019 tax year, there is no longer a penalty for not maintaining health insurance coverage for the entire year. However, this does not eliminate the requirement to report the Form 1095-A on your tax return.