Install some applications: First you will need to install hfsprogs which is a port of Apple's Open Source tools for HFS+ filesystems: sudo apt-get install hfsprogs There are only a few relatively straightforward steps to follow:
Out of the several techniques that have been suggested online I believe this one is the better choice! There are several ways that this can be accomplished under Ubuntu and I describe here one technique that I have tested on Ubuntu 18.04 and also tested the resulting dmg file on a colleague's MacOS computer.
