Facilitated diffusion - movement of materials such as glucose, amino acids through protein channels and carrier proteins in the cell membrane. Movement is from a high concentration to low concentration so no energy is needed.
Osmosis is the movement of only water from an area of high water potential/concentration to an area of low water potential/concentration through a semi-permeable membrane. No energy is needed. Example - root hair cells absorb water from soil. The high solute concentration inside the root hair cells lowers water concentration so water from the cell moves in.
Active transport - Number of different processes that require energy from ATP to transport material against the concentration gradient (low concentration to high concentration). Example - Ion pump requires energy to pump sodium ions out of the cell and potassium ions into the cell against concentration gradient.
Endocytosis is the taking in of substances by folding the membrane. Fluids are taken in by pinocytosis where membrane makes small infoldings which pinch off liquid. Large particles are taken in by phagocytosis where the cell membrane flows around particle and close off (white blood cell consuming bacteria).
The need for energy from ATP during active transport is the main difference between active transport compared to diffusion and osmosis. Another important difference is that during diffusion and osmosis material are moved with the concentration gradient, but in active transport material are moved against the concentration gradient.