Smoke came from under fridge

do not drive it , havee it checked out by a mechanic

Could be an oil leak leaking on the exhaust.

Overheat catalytic converter during your drive??????

could be that the bowel had a thin plastic protection on it when new that should have been peeled off before starting it up
could be a wire touching the hot bowel and melting
what ever , it is under warranty so take it to a service dealer or authorized repair shop and have it checked out
smoke and smell are food contaminants so the cause has to be found for safety reasons

It's probably OK to drive. I imagine they failed to get the oil filter properly seated and you're getting a little leak there. DO BE SURE to check the oil level before you drive it and add if necessary.

Has the car been sitting for a while? Have you noticed any engine noise?

HAVE YOU NOTICED COOLANT LOSS,RECENTLY?KEEP THE COOLANT LEVELS FULL,CHECK TO SEE FOR ANY LOSS AT ALL! OIL SMOKE IS MORE BLUE THAN WHITE,BUT FUEL CAN HAVE A LIGHT BLUE SMOKE.Antifreez more whitesh with a similar smell of antifreeze.

sharp acidic smell would be electrical
sweet smell would be coolant.

First of all any signs of burning on a circuit board means that a component has burnout in which case replacement will be required. Secondly depending on the colour of the stain , if its a dark colour the systems heaters are cooked in which case the cork insulation has melted the tare off and thats what you see on the floor. if its clear and oil based , the container has rusted and formed a leak ,in any of these scenarios its time to get a new one

Yes, the heating element is coming on when it shouldn't. A likely cause is the pressure pot (Level sensor sender unit) being blocked with sludge. You'll find this under the machine, either screwed to the RH side of the tub, near to the front of the machine secured by three Philips screws, or attached to the side of the big hose that goes from the tub to the pump,secured by a Jubilee clip, underneath the machine. disconnect the power and remove the pressure pot, in both cases it's a long rigid white plastic tube, from one end of which comes a narrow flexible plastic hose which goes up to the top of the cabinet and is attached to the pressure switch itself. This tube is likely to have a load of muck in it, as its bottom end. Clean this out, and if your element didn't burn out, then everything should now be fine.