Accessing Docker Volume content on MacOS

I don't think you can do it without a container. You need something along the lines of this documentation for backup:

docker run --rm --volume hello:/data -v $(pwd):/backup busybox tar cvf /backup/backup.tar /dbdata

or for modifying:

docker run -d --name access_volume --volume hello:/data busybox
docker cp access_volume:/data local-data
# modify local-data
docker cp local-data access_volume:/data

Have you known docker-compose: you can link your folder to the container by volumes you can link like this

volumes:
  - ./your_host_folder:/folder_in_container/