Here i will explain how and where to download system ISO’s
Windows
Windows 10 : ISO Downloader
Windows Server : Microsoft
Microsoft Office : ISO Downloader
Linux
Ubuntu Desktop 18.04.3 : LINK
Ubuntu Server 18.04.3 : LINK
Ubuntu Desktop : https://ubuntu.com/download/desktop
Ubuntu Server : https://ubuntu.com/download/server
Kali Linux : LINK