If you have previously "purchased" or downloaded El Capitan on your Apple ID, it may appear in your Purchased tab.
: Attempting to download OS 10.11 from third-party websites is highly discouraged (see Section 5). os 10.11 download
El Capitan focused on performance improvements, window management (Split View), a updated Spotlight search, Metal graphics API, and a revised system font (San Francisco). If you have previously "purchased" or downloaded El
Replace /Volumes/USB with the name of your USB drive. window management (Split View)