Press F1 at the check box for IAT and you will get:

1 = Foreign Financial Institution Transaction (IAT)

For this year, new banking rules prohibit taxing agencies from honoring requests for electronic funds withdrawal or direct deposit when the funds for the payment (or refund) would come from (or go to) an account outside the United States. Therefore, if this box is checked, the taxpayer must pay any amount due by check, money order, or credit card (if allowed); or if requesting a refund, will be sent a check to the mailing address on their return. For e-File purposes and for states that print the financial institution information on their forms, if the IAT indicator is checked, none of the financial institution information will print or be present in the e-File. For the federal return, the IAT indicator will have no effect on the program.   These codes are simply supplied here to be used on the state’s return. For federal/state or multiple state returns using the same financial institution, simply enter the information once in these fields.