Did you take advantage of the special CARES Act treatment of withdrawals from your retirement account for 2020? There must be something on your tax return that indicates that you had a distribution.
Form 8915-F is used to report a disaster-related retirement distribution, and any repayments of those funds. It also allows you to spread the taxable portion of the distribution over three years, if needed and report prior year distribution amounts which are to be taxed in 2021.
Use Form 8915-E if you were impacted by a qualified 2020 disaster (including the coronavirus) and you received a distribution described in Qualified 2020 Disaster Distribution Requirements, here.