please do not say it is up to u need to know the best settings for my monitor
Actually it is up to you. Much like how some people like more salt in their fries, not everyone will perceive the same image the same way which is why there's the option to tweak your settings of the display.
Your ambient lighting will also affect your panel's display output and how your eyes will perceive it. Furthermore, there are instances where people loose their eyesight for not tweaking their display according to their environment's needs, meaning ambient lighting and your eyesight.