Did you do this? -
You complete your tax return by finishing all 3 Steps in the File section. In Step 3, to e-file your tax return, you must click on the large Orange button labeled "Transmit my returns now".
After completing the File section and e-filing your tax return you will receive two emails from TurboTax. The first email when your tax return was transmitted and the second email when the tax return has either been accepted or rejected.
It just says it ready to be mailed and I can’t access my return
Ready to mail means that the tax return was not e-filed but is waiting for you to print and mail the tax return to the IRS.
See this TurboTax support FAQ for changing from mail to e-file - https://ttlc.intuit.com/community/e-file/help/how-do-i-change-from-mail-to-e-file-in-turbotax-online...