You can download the ISO file straight from Windows. That's right - everything we're going to do here is 100% legal and sanctioned by Microsoft.
If you want an English-language version of the latest update of Windows 10, you can download the ISO in this link.
If you have a relatively new computer, you probably want the 64-bit version. If you're not sure, go with the 32-bit version to be safe.
If you want a non-English-language version of Windows, or want to get an older update version, download this another ISO instead.
From your Mac terminal run this command below to see what's the disk number, for example
/dev/disk3. In my case, it's
Let's erase your pendrive running this command.
diskutil eraseDisk MS-DOS "WIN10" GPT /dev/disk2
For some hardwares you will need an MBR format, you might be able to have it running this command instead.
diskutil eraseDisk MS-DOS "WIN10" MBR /dev/disk2
Let's prepare your ISO and move the content to your pendrive running these commands.
hdiutil mount ~/Downloads/Win10_1903_V1_English_x64.iso rsync -vha --exclude=sources/install.wim /Volumes/CCCOMA_X64FRE_EN-US_DV9/* /Volumes/WIN10
You will need to use Wimlib in your MacOS, so let's install it and run it.
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" brew install wimlib mkdir /Volumes/WIN10/sources wimlib-imagex split /Volumes/CCCOMA_X64FRE_EN-US_DV9/sources/install.wim /Volumes/WIN10/sources/install.swm 3800
Now you have a bootable pen drive ready to be used on your PC.