The IRS requires you to file a tax return so you can continue qualifying for advance tax payments on your health insurance from the Marketplace. If you file a tax return without Form 8962, the IRS will send you a letter 12C asking you to send them your Premium Tax Credit information. This may increase the processing time for your tax return, including your refund if you're expecting one.
The Marketplace will send you Form 1095-A, Health Insurance Marketplace Statement, showing your premium amounts and your advance credit payments by January 31 of the year following the year of coverage. You can use the information from Form 1095-A to enter it into your Form 8962 and your premium tax credit will be calculated on your tax return.
Any advance credit payments made on your behalf to the insurance company will be reconciled with the actual premium tax credit amount.