just look at the lenses for your answers. if the lenses are completely clear, they are long range off-road lights and probably not legal to use on the street. if there is fluting in the lenses, then most likely they will be for driving or fog.
for driving, the pattern of the light is usually longer than your regular low beams and a little more intense. they give you more light farther out but not as bright as high beams.
lens fluting for fog will give a beam that spreads out more closer to your vehicle and will be much brighter closer up so you can see the street lane and fog lines more easily. some will also be yellow in color, either the lens or the bulb inside. yellow light tends to cut through fog a little better than white light overall... or so some think.
both driving and fog lights are designed to give you more light in each situation without blinding the oncoming cars. there are usually diagrams on the back or front of the packaging that show you the beam pattern and tell you what the light is for.