How do liquids and gases exert pressure upwards. Why do the exert pressure

The pressure exerted by a liquid changes with depth in the liquid. The pressure exerted by a liquid increases with increasing depth inside the liquid. The pressure exerted by a liquid is small just under the surface of the liquid. But as we go we deeper in a liquid the pressure of liquid increases.As the depth of liquid increases the weight of liquid column pushing down from above increases and hence the pressure also increases