IRS notice to taxpayers paying by check
When you provide a check as payment, you authorize the IRS either to use information from your check to make a one-time electronic fund transfer from your account or to process the payment as a check transaction.
When the IRS uses information from your check to make an electronic fund transfer, funds may be withdrawn from your account as soon as the same day the IRS receives your payment, and you will not receive your check back from your financial institution.