Make a chocolate contrate by combining the cocoa powder, sweetener and water with a spoon (you can do this directly in the cup or glass you’ll be drinking from).Mix carefully until there are no lumps of cocoa left. You'll end up with a sort of chocolate syrup (that smells amazing btw).
Add milk (hot or warm depending on your mood).
Get creative and decorate if desired! Some classics are marshmallows for hot cocoa, ice cream over cold chocolate milk and whipped cream for both options.