If you e-filed , you do not need to mail anything. If you have not filed, you can still e-file or you can print and mail the 2018 return. If you are getting a refund there is no penalty for filing after the April 15 deadline. If you owe tax due then you need to get it filed as soon as possible, since the penalty/interest began to add up after the deadline.
https://ttlc.intuit.com/questions/3399683-how-do-i-change-from-mail-to-e-file-in-turbotax-online?
https://ttlc.intuit.com/questions/1914214-can-i-print-a-copy-of-my-turbotax-online-return-before-i-f...
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS/state received the return.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
