Who's is a contraction of "who is," as in "who's there? and "the friend who’s calling," or of "who has," as in "who's got the time?" and "the friend who’s helped before." Whose shows possession, as in "whose shoes are these?" or identifies or specifies someone or something, as in "the doctor whose name I forget" and "the book whose cover is torn."

To recap, who is the pronoun used to mean “what or which person or people.” Add -’s to stand in for who is or who has. Who’s = who + is Who’s = who + has

“ Who’s ” is a contraction for “who is” or “who has.” For example, “Who’s going to the store?” means “Who is going to the store?” On the other hand, “ whose ” is used to talk about possession. It asks to whom something belongs. For instance, in the question, “Whose book is this?” we’re asking who owns the book.

The choice between these two depends on the noun that follows. If you’re talking about a singular noun or one person, use “Who has.” For example, “Who has the best score?” On the other hand, when referring to more than one person or a plural noun, “Who have” is correct. An example would be, “Who have been invited to the party?”

"Who’s" is a contraction made up of either “who+is” or “who+has”. The apostrophe in “who’s” stands in for the missing letters of “who+is” or “who+has.” You use “who’s” when you would otherwise be saying “who is” or “who has”.