This number would be found on the notice you received from the Department of Taxation and Finance.
Please see the following sample for where you would find your document locator number on the top right of the notice. It will be below the Case ID and starts with DLN.
See the following link for more information on how to respond to your letter.
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Thank you, but I have not received the letter to which the tax department refers. This letter, I have been advised by the department representative over the phone is seeking additional filing information. Since I filed through TurboTax I do not have the confirmation number, which might suffice. I have not been able to get this number from TurboTax, hence my question.