Thank you for your answer. 
Unfortunately, I would like to copy the entire directory.
To clarify my second question, I would like to have a folder system with org-mode, and therefore only use org-attach to store my documents

Le mer. 8 juin 2022 à 12:27, Fraga, Eric <e.fraga@ucl.ac.uk> a écrit :
On Wednesday,  8 Jun 2022 at 11:59, Cletip Cletip wrote:
> My question is in the object : can we attach a directory to a heading?

If you mean copying the directory and all of its contents, I imagine
not.  However, you can link to the directory if you wish by visiting the
directory using dired, say, and storing the link (org-store-link).  The
link can then be inserted wherever you wish using org-insert-link.
Alternatively, you could also tar or zip up the contents of the
directory and attach that.

> Subsidiary question: 
> Can we use org-attach as a filesystem?

What is it you wish to do?  I do not understand this question.

--
: Eric S Fraga, with org release_9.5.4-521-g1105da in Emacs 29.0.50