Here is a link to the TurboTax Expected Availability dates for federal forms. You will need to open the link and select the TurboTax version you are using and then follow the link for the expected availability date:
TurboTax Expected Availability federal forms list
TurboTax Expected Availability State forms list
Most, if not all, versions of TurboTax do already contain the 1040X as an available form in te software.
If it is not showing, maybe you have not actually filed the return yet or it was rejected and can just be fixed and retransmitted instead of having to amend it. That would be a lot easier.
