What is the type of heat transfer that causes the air to circulate in form such clouds

Heat causes particles to move faster as they have more kinetic energy. This causes particles to move faster and further apart. This means that hotter air is less dense. Cold air is denser as the particles are not so spaced out and are closer together. Therefore, cold air sinks. However, once it sinks, the particles gain heat and they rise while the hot air begins to sink. This process is called convection. It is not only how clouds are formed, but also how a heater works, which is why the heater is placed near the ground and the air-con is placed near the ceiling.