You’ll mostly find tapioca in two forms: tapioca flour (or starch) and instant tapioca (those tiny white pearls). They are not the same thing, so pay attention!
Use tapioca flour when you need a quick, smooth thickener for soups, sauces, or puddings. It dissolves instantly into cold liquid. Use instant tapioca when you want a thicker, almost jelly-like consistency in things like fruit pies or cobblers—it’s pre-cooked and doesn’t need to be ground up.