To be able to create a bootable USB of macOS, you will need a compatible USB drive with enough space on it, a Macintosh machine, and the installer file of macOS. Apart from this, having a suitable internet connection will be necessary to download the macOS installer file, and check if your Mac is capable of running the desired version of macOS. Spending some time preparing these requirements before starting the creation of the USB drive will make the whole process much easier.