1) Go to libgen.is
1) Select your genre/type (options are Sci-Tech, Scientific articles, Fiction, Comics, Standards, and Magazines)
1) Search for the book you want
1) Try to choose a file that is in .epub format (looks best on iPhone, but .pdf works too) and make sure it is in your desired language.
1) Click one of the numbers under “Mirrors” (doesn’t matter which)

Once the page redirects you, click GET. The book should then be in your Books app that comes on all iPhones.

• Gen.lib.rus.ec also works as well! It’s the mirror version I use when any others are down