Question

how to produce a ozone

Answer 1

Stratospheric ozone is formed naturally by chemical reactions involving solar ultraviolet radiation (sunlight) and oxygen molecules, which make up 21% of the atmosphere. In the first step, solar ultraviolet radiation breaks apart one oxygen molecule (O2) to produce two oxygen atoms (2 O) 

Answer 2

As well, lightning will produce Ozonethrough electrical excitation of Oxygen molecules. Ozone Generators use both forms of producing Ozone. Some generators will use electrical fields (corona discharge) to produce Ozone. Others use ultraviolet lights (UV method) to produce Ozone.