The Windows Media Creation Tool is located on the same page as the Windows Update Assistant. Click the download button and save the tool to your hard drive.
Before you run the tool, you should first check that you have met all the prerequisites and considered all the parameters necessary for creating a Windows 10 ISO file:If you plan to store your ISO file on a USB drive, you will need one with at least 8GB of storage. (Note, any data on the USB drive will be deleted and lost.)The ISO file will be a 64-bit or a 32-bit version of Windows 10 depending on the PC you use to do the creating.To use the Windows 10 ISO file, you must have a valid Product Key, so pick a version and edition accordingly.You cannot make a Windows 10 Enterprise ISO from a Windows Home or Windows Pro PC. The editions should match.You must have administrative access to run the Windows Media Creation Tool.Assuming you have met the prerequisites and are ready to proceed, you can start the tool.