Linux.com - https://www.linux.com/news/learn-create-bootable-linux-flash-drive-using-ubuntu-0
To be able to install Ubuntu or any other Linux OS or even any other OS like Windows etc, we either need a bootable FlashDrive or a DVD of the OS. In this tutorial, we will discuss how we can create bootable Linux Flash Drive using a Ubuntu System.
There are many tools on almost all operating systems available with most of them being 3rd party tools, but we have an inbuilt tool on Ubuntu for creating a bootable flash drive, called ‘Startup Disk Creator’. We will be using the same tool to create bootable Linux flash drive.