Q: I can't find iBooks application on my iPad

You have to download it from the App Store. It's free.

If you've downloaded it, but can't find it on your iPad, then have you checked all your homescreens ? Some people have needed to do a reset for it to appear (I don't know why, and I've only heard of it affecting iBooks) : press and hold both the sleep and home buttons for about 10 seconds, after which the Apple logo should appear - you won't lose any content, it's the iPad equivalent of a reboot.

I Tried a hard reset and still cannot find iBook app with my books on it.

What iOS version is your device on ? In iOS 10 it's now possible to delete the app : Remove built-in Apple apps from the Home screen on your iOS device with iOS 10 - Apple Support

If it's on iOS 8 or 9 it should be on the device somewhere, it can't be hidden or deleted on those iOS versions - if earlier than iOS 8 the app isn't built-in and can be deleted

The next step is to swipe to the right and search for iBooks in the Search field.

Have a nice day.

Try searching with Spotlight search. Also look in any folders you may have created.

I Tried a hard reset and still cannot find iBook app with my books

ok I found the iBooks app.  It was hidden in another folder but I found the app with all my books. 

I Love Apple products.