How do I put ebooks on my iPad now that iTunes does not have a books icon

I have a large collection of ebooks, some via Apple store, others via the book wholesalers and amazon. I think over 5k worth. I used to manage and pull them off iTunes when I sync either my iPad or my wife’s. I cannot find out how to pull them to my iPad. The only ones that now show up are ones purchased via the Apple store.

please send me a link on how to work with the new update, or is there a new app to rplace iBooks.

don't know what it was changed

thanks