If you selected “pay by check”, TurboTax will normally recommend that you print a form 1040-V, which is a payment voucher that you would include with your check when you mail it to the IRS. If you print a copy of your return now, or if you save a copy of your return as a PDF, it will probably include form 1040-V. The first page of the PDF will it have instructions for you.
You can also make a direct payment at www.irs.gov/payments, either by direct debit from your banking account so that you don’t have to mail a check, or by credit card (although there is a 3% service charge if you use a credit card).
