how is the ozone layer formed??

Answer 1

Ozone, a triple oxygen molecule, is formed from ordinary oxygen under high energy circumstances, for example by lightnings. or lasers, hence the production of ozone by laser printers. most ozone however is formed by cosmic radiation at the outer rim of our atmosphere. which is why it forms a thick (relatively, pretty thin compared to the total thickness of the atmosphere) layer there.

Answer 2

Ozone is formed naturally in the upper stratosphere by short
wavelength ultraviolet radiation. Wavelengths less than ~240
nanometers are absorbed by oxygen molecules (O2), which dissociate to give O atoms. The O atoms combine with other oxygen molecules to make ozone:

O2 + hv -> O + O (wavelength < 240 nm)
O + O2 -> O3