I Usually don't use PDFs in iBooks but I was happy to use it this time so I could highlight words and add notes on my ipad. I was very disappointed to find I wasn't able to do this in a PDF. I can "copy, define, and search" words. Is there a setting I need to change or a feature apple plans to add in the near future?
iPad Air 2 WiFi, Cellular, iOS 8.4
You will need to use a different app if you want to make notes and/or highlight parts of a PDF, it's not currently possible in the iBooks app.
Whether Apple will add it in the future we won't know until if/when they announce something (these are user-to-user forums) - if you want to leave feedback for Apple about it : http://www.apple.com/feedback/ibooks_ios.html
For highlighting PDFs try the Adobe app or PDF Expert. I use both apps for that purpose.
Unable to highlight a PDF in iBooks.
