To use the OS X El Capitan ISO file, you'll need to create a bootable USB drive or DVD. Here are the steps:
A cleaner, more readable system typeface. os x el capitan iso
An ISO file, also known as an ISO image, is a type of file that contains the contents of an optical disc, such as a CD, DVD, or Blu-ray disc. It's a single file that can be used to create a bootable disc or USB drive. To use the OS X El Capitan ISO