Once you have the Install OS X El Capitan.app in your Applications folder, follow these steps to create a bootable USB drive:
Mount the newly created image into your local filesystem directory: Mac Os X El Capitan 10.11 6 Iso Download
Your Mac is too new (2018+). Solution: You cannot install El Capitan on a T2 chip Mac or any Mac that originally came with Catalina or later. The firmware lacks drivers for El Capitan's kernel. You must use a virtual machine. Once you have the Install OS X El Capitan
(Replace /path/to/ with the actual location of the DMG within the installer package.) Mac Os X El Capitan 10.11 6 Iso Download