If you had an ACA plan for part of the year, and you received premium assistance which is reported in Column C on Form 1095-A, then it appears that you received advance premium tax credit and need to repay it with your tax return.
If you didn't have Marketplace insurance at all in 2023, then you didn't receive premium assistance and there should be no effect on your taxes. However, if a Form 1095-A is issued and you don't enter one on your return, your return may be rejected by the IRS.
If you determined that you received a Form 1095-A in error, you should contact the issuer to have it corrected. You can also log in to your healthcare.gov account to find Form 1095-A and other information.
See here for more information from IRS on this topic.
See this article for more information about the Premium Tax Credit.