The federal tax file deadline for tax year 2019 has been extended to July 15, 2020, due to Coronavirus (COVID-19). Go here for more information about how taxes have been affected.
During non-peak times, funds are usually withdrawn on the payment date you specify, assuming your e-filed return has already been accepted (received) by the IRS.
If that date happens to fall on a weekend or federal holiday, the funds are typically withdrawn the next business day.
Now, if you filed right before (or on) the busy July 15, 2020 deadline, the IRS may not be able to debit your payment until after the deadline, due to high e-filing volume. In addition, it can take your bank another few days to post the debit to your account.
No worries; as long as you filed your return or extension on or before July 15, 2020 and you selected July 15, 2020 (or earlier) as your payment date, you won't get penalized for late payment.
In the meantime, keep an eye on your bank account — if you still don't see the debit 7–10 days after your return has been accepted, call IRS e-file Payment Services at 1-888-353-4537 or contact your state tax agency, as appropriate.