A fixed pulley makes work easier by changing the direction of the force required to lift a load. To raise a load with a fixed pulley, a downward force is needed, which is easier than the upward force needed to lift the load directly.
A fixed pulley, also known as a simple pulley, does not confer any mechanical advantage. The force needed to lift a load is equal to the downward force of gravity on the load. Using a moving pulley multiplies the lifting force by two, meaning that only half the force of gravity is needed to lift it. A combination of fixed and moving pulleys further multiply the mechanical advantage.