You can go back to the File section to the screen where is asks how do you want to pay taxes owed, you can choose by credit card there.
You can also still mail in your returns & pay by credit card online. To pay taxes owed for Federal you can go to the following IRS website
https://www.irs.gov/payments
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To pay state taxes owed, you can go to your states website, they would have an option to pay online. You can go to your states website, or let me know what State you are in & I can get you the link.
