The return needs to be filed on or before April 15, 2020 for a calendar year trust or by the 15th day of the 4th month following the close of the tax year for fiscal year trusts. The fiduciary (trustee or other individual responsible for filing the return) selects the tax year upon the initial filing of the return.
The return would be marked final if the trust has terminated and no further returns for the trust will otherwise be filed.
With respect to documents, I have to assume that you are not a professional tax return preparer since TurboTax is not licensed for return preparation for compensation. At a bare minimum, you need the trust instrument, all financial statements, accounting records, and tax reporting statements.
