Interactive Taxpayer Assistance (ITA) The ITA tool is a tax law resource that takes you through a series of questions and provides you with responses to tax law questions. Am I Eligible to Apply for an Individual Taxpayer Identification Number? Can I Exclude Income Earned in a Foreign Country? Am I Required to File a Nonresident Alien U.S. Individual Tax Return? As a U.S. Citizen or Resident Alien Married to a Nonresident Alien, What's My Filing Status?