There is smoke coming from the crank case where you add oil. Also from where the dipstick goes. What’s wrong?
If you have smoke coming from oil cap, and the oil is foamy, exhaust gases are mixing with the oil. This comes from leaking valve stem seals or piston rings. When valve stems leak, exhaust gases can get past them, mixing with oil in the head. Some blow by is normal for piston rings, since they can’t make a perfect seal. This is normally removed by the Positive Crankcase Ventilation (PCV) system. However, worn rings leak more exhaust gases than the PCV system can handle, giving it time to mix with oil inside the bottom of the engine.