You are not to include anything regarding inherited IRA on a Form 8606 reporting contributions to or distributions from your own IRAs.
If the inherited tradition IRA had basis in nondeductible contributions, you would prepare a separate Form 8606 outside of TurboTax and supply TurboTax with the result. TurboTax does not support preparation of Forms 8606 for inherited IRAs. However, since the traditional IRA that you inherited has no basis in nondeductible contributions, no Form 8606 is to be used for distributions from this IRA. The entire amount of the distribution is taxable.
Note that if a surviving spouse inherits a traditional IRA from their deceased spouse and chooses to treat it as their own, it's no longer an inherited IRA and the balance and basis from the inherited IRA become part of their own IRAs.
