User blog comment:Taritsukii/Using Japanese Particles on the Wikia/@comment-27869316-20181116163151

Hi there! In my experience は is pretty much always written as “wa” unless you can distinctly hear that it is “ha” instead, but this is usually only the case when used in katakana as part of a loan word or in a name (ie. Haru). So for this one in most cases it’s preferable to just write wa. For を and へ it’s very case by case, more often then not I personally tend to drop the W and H and just write “o” and “e”, but there are quite a few exceptions (again, you just kinda need to listen to the lyrics and judge whether you think the sound incorporates the w and h respectively). Hope this helps!