Typically if you are receiving a refund it will show U.S. Treasury. According to the IRS, there are a few ways it can appear on your statement. For more information, please visit the IRS link below or contact the IRS directly:
I'm not receiving a refund but instead paying the tax. I did this on a credit card through the TurboTax program. I was surprised that the charge against my credit card was a payment to the "Internal Revenue Service Federal Credit Union." Maybe this is the intermediary for processing it to the treasury, but I wanted to check.
To be sure, please call the IRS to confirm receipt of your tax payment.