How do I make mobile-game-style ambient fog?

I would like to make the same kind of ambient fog, or whatever it is. What should I do ?
(The displayed game is BLUK, available on the playstore and apple store)

Have you tried simply adding a height-based global fog image effect on your main camera?

@tanoshimi No, I’m still a beginner… How should I do that ? Can you please show me.