I have e-filed. Your instructions for California are to sign and date Form 8453-OL within 1 day of acceptance. What am I supposed to do with the signed form?

Keep it for your records. Please feel free to post any additional details or questions in the comment section.

From California FTB:

"Form FTB 8453-OL, California Online e-file Return Authorization for Individuals, is the signature document for self-prepared individual e-file returns. By signing this form, you declare that the return is true, correct, and complete. Additionally, you authorize the electronic transmission of the return to the Franchise Tax Board (FTB) and the execution of any designated electronic account settlement. The form does not serve as proof of filing an electronic return - the acknowledgement containing the date of acceptance for the accepted return is that proof.

B. Taxpayer Responsibilities

Before you e-file your return, you must:

• Verify all information on the form FTB 8453-OL, including SSN(s), ITIN(s), and banking information. Reconfirm your routing and account numbers.
• Inspect a copy of the return and ensure the information is correct.
• Sign form FTB 8453-OL after you prepare the return, but before you transmit it.

After you e-file your return, you must retain the following documents for the California statute of limitations period:

• Form FTB 8453-OL
• Original Form(s) W-2, W-2G, and 1099R
• A paper copy of Form 540, Form 540 2EZ, Long or Short Form 540NR
• A paper copy of your federal tax return
• A paper copy of your other state income tax return if you claimed the California Other State Tax Credit. Refer to California Schedule S."

CA efile, message is sign and date Form 8453-OL within 1 day of acceptance. Turbotax language on page says Do not mail this form to the ftb.    ????????????????????????????

Correct, see the post right above yours. Long ago, the 8453 had to be mailed in for every e-filed return. CA has figured out they don't really want all those forms but they want you to still sign it instead of your tax return and keep it.