Installing Mojave OS On External USB Drive

I installed the new macOS 10.14 Mojave on my internal Apple SSD drive. The installation was flawless, no problems. However, some people are having issue installing Mojave on external USB drives. It is a great idea to have a copy of Mojave running on a non-essential hard drive for testing purposes. If you are having difficulty installing Mojave on an external drive, read this article which contains a fix.