Where can you find obituaries from people who died in World War 2?

All newspapers maintain a morgue of some kind. That is a copy of each edition of every paper they produced. Don't expect to fnd it on line. Some will charge for a search, some have lost their files through fire or flood and as an option, libraries at the county seat or in the state capital may contain a copy of the document that you are seeking. One of the great archives in the world regarding births, deaths and relationships and genealogy is held by the Church of Later Day Saints (LDS). They have a research staff that is skilled and cooperative.