ArsTechnica published how to make your own bootable macOS 10.14 Mojave USB install drive
A quote from the article:
All you'll need is a Mac, the Mojave installer, and an 8GB USB drive or SD card. Apple hasn’t shipped operating systems on physical media in almost a decade, but there are still good reasons to want a reliable old USB stick for macOS Mojave. Luckily, it's not hard to make one—either with a handy graphical user interface or some light Terminal use. Here's what you need to get started.How to make your own bootable macOS 10.14 Mojave USB install drive