Shall I know which kind of companies use the Comsol interface? and which modules are highly useful?

COMSOL is multi-physics simulation software. Unlike other softwares like Fluent, Aspen etc, it is not concerned with just one or two aspects of science, you can couple multiple aspects of problem in a  single COMSOl model. For example you can couple structural mechanics, electrostatics, fluid dynamics etc. in a single problem and study the effects of them all in a single model. So it depends on company which module of physics is related to its area of work.

most of nano & micro fabrication companies using comsol multiphysics to simulate any physics and engineering materials>>>>>>>>> I think4.3 family of COmsol you will need