Federal return status ready to mail
It means you selected to file your return by mail instead of e-filing. If you want to e-file, you can still switch as long as you have not mailed the return yet. How do I change from mail to e-file in TurboTax Online?
And if you meant to choose File by Mail, see How do I file my return by mail? There will be an instruction page which will be the first page of the printed return.