If you have e-filed your return, you do not have to mail in a paper copy.
In the event your e-filed return is rejected by the IRS, and is
unable to be fixed and accepted, then you would have to print, sign and
mail a paper return to the IRS.
There are some uncommon situations where additional documentation
must be mailed to the IRS with Form 8453. Please see the link below
(which may download a PDF file) for situations this may apply. TurboTax would have instructed you, if this was your situation.
https://www.irs.gov/pub/irs-pdf/f8453.pdf
