How can I de-comment my code between #if and #endif

#if !UNITY_EDITOR
//MY CODE
//Looks like comment even though that is not comment
#else
//MY CODE 2
//the code in here, looks like normal code
#endif

in this situation, how can I see all my code (MY CODE + MY CODE2) as not the comment?

The purpose of the macro is to define what should be compiled and what not. In your case, you set the !UNITY_EDITOR but you are probably in editor so this is turn into comment. And obviously the other part shows as code.

So if you want the top part to look like code and the second part to look like comment remove the ! on the front.

What is in a section that is false will always look as comment with macros.