How to copy everything from one object to other OK guys first to tell you im new with blender and i found this really cool.
I made one Pakistan flag and applied many things on it like wind, subdivision, keyframes to make it waving,
now i made another American flag and i want to apply all same effects on.
Do i have to make it one by one like i did for Pakistan flag? or i can copy all the applied modifiers from one flag to other to save my time?
( I imported images as planes to make flags)
You won't be able to copy applied modifiers, but you could try looking through your backups to find a blend file with the modifiers unapplied. 

You can read about this on the manual here.


  From the manual:
  


You can also check the folder where your blend file is for .blend1 and .blend2 files, etc. These are just backups that Blender will automatically make every time that you save your blend.