Where do u find the shared_font file on a macbook pro
You don't, this is a file that you have to dump from your own 3DS (more details here https://citra-emu.org/wiki/dumping-system-archives-and-the-shared-fonts-from-a-3ds-console/)
You need to dump it from your 3DS.
i have the file but where do i put it
It should be placed at ~/.local/share/citra-emu/sysdata.