You only need to Print & Mail your return if you selected to do so to file. If you've efiled than you do not need to go in and Print & Mail.
If you are not wanting to Print & Mail, you can follow these instructions to switch filing method and efile!
https://ttlc.intuit.com/replies/3985787
If you have selected to File by Mail, you can follow these instructions to do so on your own.
https://ttlc.intuit.com/replies/3401713