The three types of passive transport are:
Osmosis: The movement of water across the plasma membrane from a region of high water concentration to the region of low water concentration is called Osmosis.
Simple diffusion: The transport of metabolites across the membrane along the concentration gradient without the use of a carrier molecule is called Simple diffusion
Facilitated diffusion: It is a type of passive transport similar to simple diffusion in the sense that it takes place along the concentration gradient and does not require energy. However, it requires a carrier molecule (i.e. proteins of low molecular weight) for transport across the membrane.