This is quick guide howto create Windows 10 install media / bootable USB flash drive on Linux. I use here Fedora Linux, but same method works on Ubuntu, Arch, Gentoo or any other Linux too.
Reason why this guide exist is that the latest Windows 10 image Win10_2004_English_x64.iso (May 2020 update) install.wim file is too big to fit on Fat32 file system 4 Gb file size limit. Yes I know that you can use NTFS, but systems with older UEFI/BIOS won’t boot NTFS formatted USB flash drives, so it’s better create one with Fat32 file system.
This is video guide and I use here following tools, gnome-disk-utility and wimlib-tools. You can of course use example gparted, fdisk or cfdisk etc. instead of gnome-disk-utility.