Most linux iso files are hybrid iso files. It means that they can be cloned to a USB pendrive and the USB pendrive will be a bootable drive (live drive or install drive).
- In current versions of Ubuntu you can use Disks alias
- in Ubuntu 16.04 LTS and newer versions you can also use the Startup Disk Creator to clone from the iso file to a USB pendrive,
- You can install mkusb in most current linux distros,
to clone from the iso file to a USB pendrive.
from the iso file to a USB pendrive. The cloning process is straight-forward and therefore very reliable.
But Rufus has a good reputation, so I don't know why it was failing for you. Please check with
md5sum that the iso file was downloaded correctly. See this link.
The following links (and links from them) add more tips how create a USB boot drive
Download the iso file and check that it was downloaded correctly