The form that you filed with the IRS is a tax return, not a transcript. A transcript is something you can get from the IRS that shows information from your tax return, but it is not a copy of your tax return.
If you e-filed you didn't sign the tax return when you sent it to the IRS, so there is no way to get a signed copy from TurboTax or from the IRS. If you need a signed copy of your tax return, do what xmasbaby0 said: print it and sign the printed copy.
