Did it say Ready to efile or Ready to Mail? Only you can efile it. To efile you go all the way through the File tab, through the 3 steps and hit the big orange Transmit Returns Now button.
How to Efile
https://ttlc.intuit.com/community/e-file/help/how-do-i-e-file-my-personal-individual-tax-return/00/2...
If you haven't mailed it yet, you can try to switch to efile
https://ttlc.intuit.com/community/e-file/help/how-do-i-change-from-mail-to-e-file-in-turbotax-online...
