You could order service records. Information here - https://www.archives.gov/veterans/military-service-records There was a fire that damaged some WWII records, so what they have may be limited.There are various other records online, which may or may not give much detail about where they were. Some links here - https://www.militaryindexes.com/worldwartwo/index.html You might also look into local newspapers where the person or their family lived, because sometimes there will be mentions about where they were during the war or if they were injured.