Do I need to mail anything after I've e-filed?
Not unless we tell you to. The goal of e-filing is to eliminate as much paperwork as possible.
There are a handful of situations where you might have to mail something after e-filing, for example if your return contains Form 8453.
If yours is one of them, we'll let you know. Otherwise, don't worry about it.
We do recommend that you print your return for your records after your e-filed return has been accepted.