The IRS extension for filing a 2023 tax return was on or before October 15, 2024. After that date a 2023 tax return or amended tax return can only be printed and mailed.
If you filed a 2023 tax return and now need to amend the return -
Before starting to amend the tax return, wait for the tax refund to be received or the taxes due to be paid and processed by the IRS.