Where can I verify the payment I set up for my federal taxes?

You can find this information in the Filing Instructions document (or Electronic Filing Instructions document) which can be printed out as part of your tax return paperwork.  The tax payment method (payment date, bank account, etc.) will display on the page, at the top of the Balance Due/Refund section. 

If you did not print the filing instructions, you should be able to get access to them in download all forms and worksheets. 

If you do not see a date, It will normally default to April 15th. You can contact the  IRS e-file Payment services at 1-888-353-4537 for assistance.