When you download Windows from Microsoft Store, you have two options: You can download a collection of compressed files, or you can download an ISO file.
An ISO file combines all the Windows installation files into a single uncompressed file. If you choose to download an ISO file so you can create a bootable file from a DVD or USB drive, copy the Windows ISO file onto your drive and then run the Windows USB/DVD Download Tool.
Then simply install Windows onto your computer directly from your USB or DVD drive.
When you download the ISO file, you must copy it onto a USB or DVD.
When you're ready to install Windows, insert the USB drive or DVD with the ISO file on it and then run Setup.exe from the root folder on the drive.
This allows you to install Windows onto your machine without having to first run an existing operating system.
If you change the boot order of drives in your computer's BIOS, you can run the Windows installation directly from your USB drive or DVD when you first turn on your computer.
Please see the documentation for your computer for information about how to change the BIOS boot order of drives. To install the software, you can make one copy of the ISO file on a disc, USB flash drive, or other media. After you’ve installed the software and accepted the license terms that accompany the software, those license terms apply to your use of the software.
The license terms for Windows permit you to make one copy of the software as a back-up copy for re-installation on the licensed computer.
If you do not delete your copy of the ISO file after installing the Windows software, the copy of the ISO file counts as your one back-up copy.