My 1996 landrover discovery is smoking when I am in park but once in drive there is no smoke. The smoke is white. What could be the problem?

Sounds like you have a small amount of coolant getting into the combustion chamber/s. This could be a crack in the head or a blown gasket. You should have a mechanic look at it.

What a year and mileage ,could be head gasket .I try head gasket fix,works for me.

There is either A).an oil leak or B). the smoke is from residue oil spilled on exhaust and such during the repair. Crank the engine and look everywhere for an evident oil leak if one is not found leave it run till it gets hot enough to show where the white smoke is coming from and see then if it is residue or a new leak. Remember to rate my answer and leave testimony this is how we earn our milestones here of FixYa remember we are all volunteers here so answers may not come as fast as you like please be patient thanks in advance.

valve seals allowing oil into cylinders
oil ring on piston broken
worn valve guide in head
blue smoke means ur burning oil
black smoke burning to much fuel
white smoke burning coolant
the landrover part makes my wallet hide
leaving it will only foul up your plugs,crud up inside the engine
and eventualy kill it. no quick cheap fix there sorry

replace ignition coil, spark plugs, also double chek your coolant temperature must be normal. overheating causes car slows down and engine cant handle excessive high temperature or may damage it.

It seems to me that you either have a dirty injector. Maybe you should try using those cleaning additives to the fuel. Tank it up full.

Check your engine oil cap and see if the inside of it has yellowish gooey & slimey build up in it. If so you coolant is leaking in to your engine oil

If the smoke is from the LH front wheel area it could be the parking heater exhaust. This is normal to see in cold weather conditions.

its the capasator needs replacing you blew it up.

Plenty off coolant in reservoir? Does the car overheat during normal driving or only on trips?
Does the car run rough and do you have white smoke coming from tail pipe?
If not then it could be 2 possible items
First check the viscous fan clutch is no frozen, this is the unit in the middle of the plastic fan, it should spin freely with a slight bit of tension. Or the radiator more and likely is clogged, I would suggest you remove the radiator (or get your mechanic too) and get it rodded-out.
Hope this helps, and don't drive the car hot, you could cause major engine damage on this vehicle if your not careful.