Even if you tell TurboTax you intend to pay any Federal tax due by check, you are not obligated to pay later with a paper check. If you want to pay electronically for free, you can pay at the IRS Direct Pay website, and it will take it out of your bank account in an ACH electronic transaction. It's free for a direct debit of your bank account, but there is a service fee if you use a credit/debit card there.
https://www.irs.gov/payments
In the form you would indicate for "reason" that you want to pay "tax return", and then for "apply to" choose Form 1040/A/EZ, then choose the correct tax year. At the end print out the confirmation for your records.
Or if you have an account (or establish one) at the Treasury's EFTPS system, you can make electronic payments there for tax due from a Form 1040, or for 1040-ES estimated tax payments throughout the year, etc.
https://www.eftps.gov/eftps/
