if you put ' in it, that's not plural
it means that it's possessive, belonging to somebody
for example, ARMY
most of us just say ARMY even for plural, but I've also seen ARMYs used
ARMY's means belonging to ARMY
there's a taglist on here that I didn't apply to be in because it has a typo
I know I'm weird, so sorry
When you learn English as a second language, they basically grab you by the neck and make you learn these things
often we know the difference between "your" and "you're" better than a lot of native speakers (is something that I've both noticed and have been told) because you'd genuinely get failed in class if you put the wrong form
so it bothers me to see the mistakes