Macro operation on files, Pasting

If you could answer me this small and annoying question, I would greatly appreciate it.
I have no knowledge of Python, and I only work with macros. Is it possible to operate a macro on files, so that a certain section will be pasted in each file. I have a lot of audio files that I want to paste at the end of them a certain extension. But when I operate for example the following macro:


It does nothing but export the file.
Although I checked and he has the requested section in memory.
If you have knowledge on the matter, I would be very grateful