How to import .COPY or .T3D File that you exported from UE4 Project?

Does anyone used or imported** “.COPY / .T3D”** file which gets exported from Asset actions in UE4? Any idea how this .COPY file can be used?
For example: If I want to export Material function or Blueprint from Asset action, it exports with .COPY / .T3D extension. But importing is not working with the same extension.