I use my iPad as PDF reader, so my iPad contains many PDFs which I'd like to sync.
It should be the steps below:
- You need to login with correct Apple ID on every device you want to sync
- Plug in iPad/iPhone to your Mac (my situation)
- Open iTunes
- In iTunes go to File → Devices → Transfer purchases from <iOS device>.
But iTunes copy all my apps, not only books or PDFs.