Short-term testing (90 days). Microsoft allows IT pros to download a 90-day trial of Windows 10 Enterprise LTSC 2019 (Build 1809).
Enterprise admins with an active Volume Licensing agreement. If your company owns a license for Windows 10 Enterprise LTSC 2019, you can log into the VLSC portal, search for "Windows 10 Enterprise LTSC 2019," and download the 1809 ISO directly. This is the only 100% legitimate, untampered source. Download Windows 10 1809 Iso