If you're installing Windows on a computer that doesn't already have macOS or Windows (for example a PC running Linux, or a brand-new machine), you can still create a bootable Windows USB installer directly from your Mac. This guide walks you through the whole process using a free tool called WinDiskWriter.
What you'll need
A Mac (Intel or Apple Silicon).
A USB drive with at least 8 GB of space (its contents will be erased).
A Windows ISO file, which you can download from Microsoft's official website.
Step 1: Format your USB drive
Open Disk Utility on your Mac (Applications > Utilities), select your USB drive, and click Erase. Use the following settings:
Format: MS-DOS (FAT)
Scheme: Master Boot Record (MBR)
If you don't see the Scheme option, click View > Show All Devices, then select the USB device (not just the volume) before erasing.
Step 2: Install WinDiskWriter
Download and install WinDiskWriter for macOS from the official page: https://github.com/TechUnRestricted/windiskwriter.
Step 3: Select your ISO and USB
Open WinDiskWriter, then choose your Windows ISO file and select the USB drive you just formatted as the destination.
Step 4: Write the image to the USB
Click Start to write the image to the USB drive, and wait for the process to finish before removing the drive.
Step 5: Boot and install Windows
Insert the USB into the target computer and boot from it (usually by pressing the boot-menu key, such as F12, F9, or Esc, during startup). Follow the on-screen prompts to begin the Windows installation.
Note: WinDiskWriter is a free third-party tool. It automatically handles large Windows installation files, so you don't have to worry about the FAT32 file-size limit.