If you e-filed, you would only need to mail in anything in the following situations:

1. There is a specific form that must be mailed in, such as Form 8332 (when one parent allows the other parent to claim a child on his/her tax return).  There are other situations, but they are rare.  TurboTax will advise you if you need to mail in a particular form.  If you had no message, you have nothing to worry about.
2. You are paying tax due, either for Federal or State, and have elected to mail in the payment.  A voucher will print out for you to include your payment.
3. In response to correspondence from the IRS or state tax division.

Otherwise, you will not need to mail in anything.  You will receive a Form 8879 which you must sign and keep for your records.  You don't send that form or any other tax documents to the IRS, however, unless they specifically request it.