As I use Pycharm to develop my python files it is handy to have a method that uses finder to manage the files. Hard-core folks might be happiest with emacs and scp etc.
So, on the Raspberry Pi. run:
apt-get install netatalk
Then on the Mac in a terminal:
open afp://192.168.1.100replace the above ip address with that of your Raspberry Pi.
This will install Apple talk protocol onto the Pi which means that the Pi can appear in the Finder.