Force is a push or pull. Weight is force, as it's mass pushing on a surface due to gravity. Pressure is force divided by the area over which it acts. Here are a few examples:
1. Atmospheric pressure can be expressed in psi, which is pounds per square inch. This unit illustrates that the force (weight of the atmosphere above) is divided by the area over which it acts, in this case one inch squared.
2. Snow shoes keep people on top of the snow be decreasing the pressure on the snow. A person's weight, which is the force being applied, is the same with or without snowshoes. The snowshoes are much larger that the person's feet so they spread the weight over a larger area.
3. Spike heels on shoes are known to leave indentations in soft flooring such as wood and to sink into soft ground. Because the area of a spike-heeled shoe that's in contact with the ground is smaller than that of a regular shoe, it increases the pressure on the ground without no change in the force (shoe wearer's weight.)