Hi,
Generally lights in Shapespark only affect the lighting of the scene, they don’t add any geometry themselves. So if, for example you want to add a light bulb which emits light to your scene, then you have to add such an object in your 3D editor and then add lighting in Shapespark either by making the light-bulb material emissive or by adding a point light and by enabling ‘isolate shadows’ for the light bulb object.
You can read more about lighting in Shapespark here: