
You can download a Windows 10 Disc Image (ISO File) from Microsoft

In the dialog, enter a name for the drive, choose MS-DOS (FAT) from the Format pop-up menu, choose Master Boot Record from the Scheme pop-up menu, then click Erase.A full-installation, 64-bit version of Windows 10 on a disk image (ISO file) or other installation media. (If they aren't available, use a USB keyboard and mouse.) A blank 16 GB or larger external USB 2 flash drive, formatted as MS-DOS (FAT).To format an external USB drive as MS-DOS (FAT), use Disk Utility, located in /Applications/Utilities.In Disk Utility, choose View> Show All Devices, select the USB drive in the sidebar, then click Erase in the toolbar. The keyboard and mouse or trackpad that came with your Mac You can use Boot Camp Assistant to install Windows 10 on your Intel-based Mac.You need an external USB drive to install Windows on older Mac computers.To find out whether you have a Mac that requires an external USB drive, see the "Learn more" section in the Apple Support article Install Windows 10 on your Mac with Boot Camp Assistant.If your Mac is a newer model that doesn't require a USB drive, follow the instructions in Install Windows on your newer Mac using Boot Camp instead.

Install Windows on your older Mac using Boot Camp
