When you Print or Download your return, your Routing Number and Account Number are shown at the bottom of your Form 1040.
If you entered a wrong bank account number, you can go online to pay your tax due.
Here's the link to pay the IRS:
https://www.irs.gov/payments/pay-taxes-by-credit-or-debit-card
Click on your state in the FAQ below:
https://ttlc.intuit.com/replies/3302452