Stabilisation reduces the effects of camera shake. It can be divided into digital and optical stabilisation, the latter being part of the structure of the lens.
Digital stabilisation uses software to reduce the effect of little movements, which involves increasing the camera's sensitivity to light (ISO). Optical stabilisation, on the other hand, is based on the movement of the lens in the optical system, which compensates for the effects of camera shake. Optical stabilisation is the more effective option.