how to download os x el capitan

El Capitan is only available for download if you have Mac OS X 10.6.8 via the App Store, or a computer computer that was released between September 30th, 2015 and September 20th 2016 via the Internet restore of command-shift-option-R while connected to the internet, and wiping the hard drive HFS Journalled. APFS formatted drives will not install Mac OS X 10.12.6 or earlier, and vice versa, these systems can't see APFS formatted systems and 10.13 or later systems that are on SSD.

Some key dates to remember.

August 28, 2009 to March 15, 2010 - Apple released a 10.6.3 retail disc that looks like this that will install on these machines, and older machines that can be updated to 10.6.8 via the combo update to bring the App Store for El Capitan download.

March 15, 2010 and July 22, 2011 - Apple released system specific CD for Macs released during the period or USB key that installs 10.6.4 to 10.6.8 that the 10.6.8 combo update can bring you to the point you can install El Capitan. Missing those discs will force you to install Sierra, Mac OS X 10.12 on top of 10.10.5 or earlier on these machines and later machines until September 30, 2015 to get El Capitan. Note for any machine older than July 22, 2011, upgrading past 10.6.8 gets rid of Rosetta 1, the background application that made those machines compatible with applications for pre-January 7, 2006 Macs.

Machines that are newer than September 15, 2016 can't run El Capitan.

Machines which can run El Capitan are covered in my FAQ*:

http://www.macmaps.com/docs/DOC-13695/

Other El Capitan pitfalls are covered here:

https://discussions.apple.com/docs/DOC-8811

*Links to my pages may give me compensation.