How to open native file manager

Hello to everyone, i’m trying to save a custom file on my android device but i’m looking for a way that opens the native file browser so that the user can decide where to save the file.
How can i do that?
the file is a json with a custom extention.

Intent.ACTION_CREATE_DOCUMENT is the thing you want to use

how can i do that in unity?

If you want to write it by yourself