You get extra time to file your Wisconsin income tax return while you are serving away from home. Serving outside the United States and Puerto Rico on the filing deadline gives you a two month extension. Serving in a qualified hazardous duty area while drawing combat or hazardous duty pay gives you a 180 day extension, counted from the later of your last day in the combat zone or your last day of continuous hospitalization for injuries from that service, plus the days that were left in the filing period when you entered the combat zone.
There is nothing to file in advance. File your Wisconsin return within the extension period and note your qualifying service on it.
Your orders or Leave and Earnings Statements showing the dates and location of your service, and hospital records if you are counting a period of continuous hospitalization.
