If you have no income for 2021 other than SSDI you are not required to file a tax return.
If your only income has been Social Security you would only be required to file if you received a 1095A for having Marketplace health insurance.
You have to file for your health insurance you pay for?
As indicated by @xmasbaby0, if you have a Form 1095-A, you must file a tax return. Otherwise you may not be required to file a federal tax return and the same might be true for your state return.
TurboTax will walk you through the entry if you are required to file. IRS Request for Form 8962
If you receive a Form 1095-A, Health Insurance Marketplace Statement, showing that advance payments of the premium tax credit were paid for coverage for you or your family member, you must file an individual income tax return and submit a Form 8962 to reconcile those advance payments, even if you would not otherwise be required to file a tax return. You also must file an individual income tax return and submit a Form 8962 to claim the premium tax credit, even if no advance payments of the premium tax credit were made for your coverage.
State returns may have a property tax or rent rebate credit report, or possibly another type of special return for low income or senior citizens.