Engine smokes and use a lots oil. I would like to know how to repair this problem?

Usually by buying a new engine (thats usually the cheapest route). Or paying a mechanic with the tools and equipment to properly rebuild it.

Hi,
It really depends on the age and type. Older engines could liable be worn out. Newer OHV engines could have a blown head gasket.
At any rate a point of perspective is important. The oil comes from the crankcase which is generally a sealed environment. It suffers from pressure waves as the piston moves up and down. It is vented, but not openly, only in a controlled manner. When the piston moves upward, a vacuum is created. When the piston moves down, a pressurized situation exists. Both of these are from the perspective of the area beneath the piston. When it is under pressure beneath the piston, oil can be pushed by the rings. If air enters when the piston is near the top of its stroke, the result can be the same. If the rings are not worn out, then air is entering at an inappropriate time.
If it is old, then a search of wholesale mower engines will yield five or six warehouses that specialize in them.
Peace,
Clarke