iBooks App: The Ultimate Guide
How do you sample, download, highlight, and customize your ebooks, PDFs, and audiobooks with Apple's iBooks app? We'll show you!
Updated March 2017: Added information for iOS 10.3, PDFs, and sharing.
iBooks is several apps in one: It lets you find and buy ebooks and audiobooks in the iBooks Store; organize, view, and sync them in the iBooks reader; and download and view PDFs. You can customize the reading and listening experience, including paper, and even organize your files into collections. If you want books that are as simple to get and enjoy as iTunes media or App Store apps, you want iBooks on your iPhone or iPad!
iBooks: The Ultimate Guide
How to download and read iBooks
How to listen to audiobooks with iBooks
How to share books and excerpts from iBooks
How to change the format of your iBooks
How to customize iBooks
How to sync content with iBooks
How to manage your iBooks library
How to sell your ebooks in the iBooks store
How to troubleshoot iBooks problems
Source: iBooks App: The Ultimate Guide