Sometimes, this could be as simple as water vapor or steam exiting your exhaust system. It could also indicate other problems. Here are some guidelines: http://caradvice.askpatty.com/ask_patty_/2009/01/do-you-know-when-to-worry-if-your-car-is-smoking-from-the-exhaust-pipe-.html
If these tips are not helpful, then have your trusted mechanic take a look.
If this is accompanied by a rough idle, you may need to have your head gasket inspected.
〉 Answered on Feb 9th, 2016 by Amanda J. Pierce, MBA "AJ", Certified Mechanic, Project Coordinator; Primavera Scheduler at VIGOR Alaska Industrial Shipyard & BizzM3ch Solutions
Smoke out of the tail pipe on a cold morning is normal, as long as it goes away or is significantly reduced after a 5-10 minutes of driving.
Check the coolant level. If the coolant is low and the smoke does not go away, or gets worse, the head gasket may be leaking coolant into the engine. This should be diagnosed and repair by a reputable repair shop.
〉 Answered on Feb 9th, 2016 by Helaine Kurot, Owner/Technician at 360 Automotive