To download and set up , you should primarily use the official Apple-provided disk image (.dmg). While ISO files are common for virtual machines, Apple officially distributes the software as a DMG. Official Download Links
Download OS X El Capitan 10.11.6 Combo Update - Apple Support mac os x el capitan 1011 6 iso download gratis work
Before installing, ensure your hardware is compatible. El Capitan supports: How to Download OS X El Capitan 10.11 (DMG, ISO, APP) OS X El Capitan 10
If you get an error saying the installer is damaged, it’s often a certificate issue. Open Terminal and use the command xattr -c [drag installer here] to clear attributes. If you cannot obtain the installer, an Apple
Apple provides a direct download link for the OS X El Capitan disk image. This is the safest way to ensure your file isn't corrupted or infected with malware.
If you are trying to boot on unsupported hardware (like a 2006 Mac mini or a non-Intel PC without Hackintosh patches), the ISO will never work.
Visit the Apple Support website and look for the "How to download macOS" page. They provide a direct link to the OS X El Capitan installer.