I originally filed my 2023 CA tax return using Turbotax online. Now I am working on 2023 CA amended tax return using Turbotax Mac version. I've finished all the corrections and am ready to submit my amended return, but Turbotax doesn't allow e-filing because the the e-filing period has ended. The Turbotax instruction states that "sign and date form 8453-OL". However, it also advices against mailing a paper copy of the return. I'm confused about what and how I should submit CA amended tax return.
To amend a California tax return, use California Schedule X. Schedule X is available for the Mac version of TurboTax, but is not supported for e-filing; therefore, you would need to print and mail the form with the supporting returns.
See here for the current availability of forms for Mac users.
Beginning in taxable year 2023, the Schedule X, California Explanation of Amended Return Changes will be year specific. If you are amending a prior year tax return, get the Schedule X for the applicable tax year. See here for the instructions for California Schedule X.
You indicated that you have already made the corrections. See this TurboTax help article for more information on how to amend a prior year state tax return.