Form 673 is your ticket to claim an exemption from U.S. income tax withholding on your wages abroad. When you work overseas and qualify for the foreign earned income and housing exclusion, this form comes to your rescue. By handing it over to your U.S. employer, they'll adjust the federal income tax withholding from your pay accordingly. No one likes to pay more taxes than they should, and this form ensures you're not overtaxed on your hard-earned income from working abroad.