Across the U.S., Postal Serviceâ„¢ PO Boxes are available in five sizes. A homeless person may submit an application for PO Boxâ„¢ service to a local Post Officeâ„¢.The Postmaster may approve the application under certain conditions. Either option will eliminate waiting in long lines on election day. Fill out and submit PS Form 3575, available at any U.S. Post Office. Post Officeâ„¢. Share. San Antonio, Texas 78207-6328. Please complete and return your application no later than 11 days prior to the election for which the ballot is being requested. Complete our EPIC Scholars Application to get matched with eligible scholarships. Be sure to also check out the list of available Individual Scholarships.