On a wheel and axle, where do you put the force in order to decrease distance and increase force?

About the wheel and axle problem, there is a term, called mechanical advantage (usually write as MA). And the equation is MA equals to the ratio between the force on the wheel and the force exceeded on the axle. Because the variables to calculate the force are all the same except the radius. So, we can write the equation as MA=R(out)/R(in). To increase force and decrease the distance is to apply force on axle.