Having white smoke coming out of your exhaust is a sign that your burning coolant and is most likely caused by a blow head gasket.
Be sure to check your coolant level because your coolant is likely getting through your head gasket and into your cylinders which then gets burnt off in the combustion process.
You can use some head gasket sealer in a bottle to fix your head gasket if it's not severely blown but a completely blown head gasket will require head gasket replacement which can be costly.
If it's just smoking white smoke out the exhaust and not overheating then the head gasket sealer in a bottle will almost always fix the blown head gasket issue as long as you follow the directions carefully.
I have used Bar's Stop Leak Head Gasket Sealer with success and the car that had a blown head gasket is still going strong after 5 years when I put the head gasket sealer in.