If it says Ready to Mail then it has not been filed yet. So you can go back in and change it. Then print it out to mail or try to switch to efile. Click on Add a State to let you back into your retun.
How to to switch to efile
https://ttlc.intuit.com/community/e-file/help/how-do-i-change-from-mail-to-e-file-in-turbotax-online...
Turbo Tax will always say Printed or Ready to Mail. They don't know when or if you actually mailed it and the IRS doesn't tell or update Turbo Tax when they get your return.
If you want to mail a return from the Online version
https://ttlc.intuit.com/community/printing/help/how-do-i-print-and-mail-my-return-in-turbotax-online...
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 received the return. Don’t forget state.
Important! Mail Federal and State in separate envelopes and mail each year in separate envelopes.
