Below PFP - A face with a plus to show "add reaction to message" when clicked, a menu below button shows 6 reactions, a like, heart, sad face, shocked face, scared face, and angry face. When reaction picked, the people counter (numbers) goes up, and your reaction is displayed, highlighted. ALSO, you can click the stacked reactions (basically people's reactions, for example, like heart and scared are stacked), and see which users reacted with what reaction.
