Tapioca is a starch extracted from the cassava root through a process of washing and pulping. The most common use of starch is to add to puddings or mix with fruit.
Cassava flour comes from ground cassava root. It's fine and powdery which is mainly used as a swap for all-purpose flour in gluten-free baking.
This is the most common form in which dried cassava roots are marketed and most exporting countries produce them. The chips are dried irregular slices of roots that vary in size but should not exceed 5 cm in length so that they can be stored in silos. They are produced extensively in Thailand, Malaysia, Indonesia, and some parts of Africa.