Form 1040-V: Payment Voucher is an optional IRS form that you include with your check or money order when you mail your tax payment.
If you have not yet filed your tax return, you can have the Federal payment deducted from your bank account if you choose. When you reach the File section of your tax return, you will see a question that asks "How would you like to pay your Federal taxes" You can choose the direct debit option or you can select the option to mail a check.
If mailing a check you would then mail the Form 1040-V along with your check payment. Here is an FAQ with additional information on how to pay your Federal Taxes How
can I pay my Federal taxes.
As an alternative or if you already filed your return with the IRS, you can pay online by visiting https://www.irs.gov/payments and choose a payment option instead of trying to pay through TurboTax.