I accidentally filed my return with another tax service and I didn’t mean to do that. I wish to e-file with TurboTax instead. Do I need to submit a 1040x? Where do I do that? How can I fix this s

If you filed with another tax service and it was accepted by the IRS and your tax return was correct as for as you know, you can't file another return with TurboTax. If it was rejected, you can start over using TurboTax.

If it was accepted but was incorrect and needs to be changed, you can use TurboTax to complete an amended return form 1040X. But it would be very difficult to use TurboTax because you must first prepare a return using TurboTax that is identical to the return that you filed originally with the other preparer. That can often be hard to do especially if there are mistakes in it. You would be better served by amending it using the original tax preparer service.