Just to clarify, did your weather temps recently change? Perhaps it got much cooler? It's not abnormal for cars to produce a mist/puff of smoke when started in cold weather. Kind of the same principal as how our breaths are able to be seen in cold weather.
If it's not due to weather, white smoke typically means you are burning antifreeze which would indicate a blown head gasket.
Two times since I bought mine it has blown a little oil out the exhaust on start. I have no clue why and there was no rhyme or reason to it. Once when it had around 2k miles in the middle of winter and once with 11k miles in summer.
I have no oil consumption so I just chalk it up to one of those weird things.
This is not uncommon. I see this every now and then with cars, new and used, on the lot, and even on removal from the transporter upon initial delivery to the dealership. Do not fret, there is no problem, unless you are seeing loss of coolant or high oil consumption. Counterman.
Water Build up in the exhaust.
If you get it hot it should quit.
When it cools you will get some condensation build up so when you start it again it will smoke until hot again.
If it's real cold out it may never really quit but will lesson.
However, you could have a bad Head gasket which could be leaking antifreeze into the oil.
Check your oil level, if that is good then you should be o.k..
When I got my SRT8 Challenger, it had a little light blue smoke at start up. I installed a catch can, and that solved the problem. The PCV valve puts a little oil in the intake. The catch can keeps oil from getting into the intake.