You do not need to mail your returns if you e-filed.
E-filing (electronic filing) is a paperless, secure alternative to filing a paper return.
When you e-file with TurboTax, you enjoy industry-standard encryption technology to safely and securely transmit your return.
E-filed returns are usually processed more quickly than paper returns, which is good news if you're expecting a refund.
E-filing is also "greener" than paper-filing – not only do you save paper (often lots of paper), you save the gas and energy required to transport paper returns.