For some reason, there seems to be a prevailing desire to use apostrophes to indicate a plural form of words. There are very few times this is accurate, the most significant one being making letters of the alphabet plural. Of course, this is logical since there is a large difference between a’s and as or i’s and is, lol.
Generally, an ‘s indicates possessive, as in “the dog’s ball” (which, of course leads to the conundrum of how to make “dogs” possessive, i.e. the two dogs’ ball).
Apostrophes are also used for contractions, to represent missing letters, as in can’t (where the ‘ indicates the missing “no” in can not/cannot) or isn’t (‘ indicating the missing space and “o”).
(Then there is the whole single quote vs double quote issue but that’s an entirely different subject!)