Individuals – If you are a U.S. citizen or resident alien living and working (or on military duty) outside the United States and Puerto Rico, file Form 1040 and pay any tax, interest, and penalties due. Otherwise, see April 15. If you want additional time to file your return, file Form 4868 to obtain 4 additional months to file. Then file Form 1040 by October 15. However, if you are a participant in a combat zone you may be able to further extend the filing deadline.