The buoyant force on an object submerged in a liquid depends on

the pressure exerted by the fluid on its submerged surface

Explanation:

Flotation Force (Archimedes Principle):

If we have a body floating on the surface of a liquid or completely submerged inside it, the resulting force that keeps that body in position is called the "Flotation Force."

When a body is fully submerged in a fluid at rest, the fluid exerts hodrostatic pressure on each of the body parts in contact with the fluid. By the basic equation of the Fluid Static, at the same level h the forces exerted on the body due to the pressure are compensated, since they are equal in magnitude. However, the pressure exerted by the fluid on the lower part of the body will be greater than that exerted on its upper part, so the corresponding forces are different in magnitude and are not compensated. The resulting force due to the difference in hydrostatic pressures between level h2 and level h1 is the buoyant force. That is why this force always acts in a vertical and upward direction. If the floating body does not move, the floating force will be balancing the body weight.

Experimentally it can be verified that the buoyant force does not depend on the material from which the submerged object is made, but on the hydrostatic pressures exerted by the fluid on the volume of said object. That is why we can replace it with the surrounding fluid with its same shape and volume. This portion of fluid will experience the same state of pressures as the body in question.