the engine smokes but runsvery well could it be rings or something else

Hello, What color is the smoke, and when does it smoke the most? These two questions are basic, but can shed a great deal of light on the situation when there is smoke pouring from the engine. The main causes of smoke from the exhaust is the engine burning coolant, oil, or too much fuel. Respectively, the colors are white, blue-gray, and charcoal-black.