If you are seeing "Ready to mail," it means you chose the File by Mail option instead of e-File or your return is not eligible for e-filing. So you will need to print and mail your return if you choose to file a paper return or if your return is not eligible for e-file.
If you chose the File by Mail option by mistake, you can switch to e-file using the steps below. Click on "Change to e-file your return in TurboTax Online versions" below and it will show you the instructions for how to do that.
NOTE: If you try to switch to e-file and it doesn't allow you to, you can find some reasons listed here https://ttlc.intuit.com/questions/1901497 that would be the cause for not being able to e-file your return. And in this case, you need to print and mail.
