Burning Ubuntu 18.04 ISO to USB on macOS
Hi! The Tutorial shows you Step-by-Step How to Burn Ubuntu 18.04 Bionic LTS ISO to Bootable USB Stick on macOS Systems.
And to Create a GNU/Linux Bootable USB Key on a Mac I’ll Make Use of the Unetbootin USB Creator Tool.

Download & Install UNetbootin Bootable USB Creator.
Run Unetbootin.
Browse for Linux ISO.
Select the Right USB Stick Device.
How to Find USB Device Node on macOS:
Click on OK to Start USB Creation.