Other way around.
It's low on oil, BECAUSE it's smoking and burning up the oil.
Something in the engine (piston rings or valve guides probably) is wearing out and letting a tiny amount of oil get into the cylinders. This makes smoke, and the oil is gone.
So although you need to top up the oil, to stop the engine seizing up totally, this wont fix the smoking and oil use problem. But you can keep the car going for a while as you save up to replace it. Rebuilding or replacing the engine on a 15 year old Ford probably isn't worth it.
Absolutely. It is probably a sign that a ring or two on your pistons is broken or cracked. Not unusual for a 15 year old car. If you are not consuming a lot of oil between oil changes, start putting aside some money for an engine rebuild or vehicle replacement.
Certainly it could. You could have a oil leak that is hitting a hot surface causing the smoke. However, there are a number of things that could be the cause. Best have it inspected by a certified mechanic.