1095-A and 1095-B are tax forms that may be used to file your taxes concerning your health coverage.
When applying for health insurance you were asked to estimate your income and based on that estimation you may have been offered a subsidy. Those who received a subsidy and got their plan from the marketplace will receive a 1095-A. You will need this 1095-A to file your tax form 8962 as well as determine whether you owe or are entitled to a reimbursement based on your income estimation when applying.
Individuals who applied for insurance off the marketplace will receive a 1095-B. These are sent to the covered individual direct from the insurance company. If you don't receive a 1095-B don’t worry, carriers are required to report your coverage information directly to the IRS and may not send you a copy. Because insurance companies report directly to the IRS a 1095-B is not a required form to file your taxes.
Subsequently there is also a 1095-C as well. This is for people who had group coverage from their employer. As with the 1095-B, the 1095-C is directly reported to the IRS by your employer and is not required to file your taxes.