After you file

The option to pay for TurboTax using your federal refund may not show available if your return contains IRS or state forms that have still not been finalized yet. You’ll also need to have chosen the e-file option and you'll need to have a federal refund coming that is large enough to cover all fees. Otherwise, you'll need to pay with credit card.

You should be able to click on Review to the left, and it will show you a list of forms in your return that aren’t available yet. It should also show date they should become available. If all forms in your return are finalized, then go here Why can't I deduct my TurboTax fees from my refund? for more reasons why you may not have the option.

Keep in mind, the IRS will not start accepting e-filed & returns until January 29, 2018.

Once option is available, you can use the steps here Can I pay with my refund? to help you with how to pay with refund.