How to edit a rotated mesh in pose mode I want to edit a mesh of a rotated object in pose mode. 
But when I select a rotated object with edit mode, it is restored to its original condition.
I want to make an animation process of folding, so I could't press apply button after rotated armature.
Please give me an advice.
Select the armature, go to the Modifiers tab. I think you are looking for this:



Some operations (such as loop cut) may not work as expected on deformed edit mesh display, so, be careful when editing.