You can also add PDFs to your iTunes library on your computer by dragging and dropping the PDF into your iTunes Book library. The files will appear when you are preparing your device to sync.
I have also done this in the past with epubs from non-Apple sources. But for nearly a year, I can't do it. There are several possibly related issues:
- In iTunes, the PDFs and pubs I have added recently do not appear in the checklist of items available to sync. Those added before the problem started still appear. I have sorted by date, title, and author and can't see them. I look in iBooks and verify they are there.
- There is at least one book for which there is one copy in iBook on the MacBook, but iTunes says there are two. Checking them both makes two copies on the iPad.
- If I select only PDF in iTunes, it says there are none. But there are many on each device.
- At least two items that are already on the iPad are not checked in iTunes.
I can mail things to myself, and "open in iBooks" on the iPad, but that's a bit of proctalgia. If I turn on "save to iCloud," items are automatically on both, but only that ones that go up first, because my space fills up. And I don't get to decide which ones go first.
I can use Microsoft One-Drive or Dropbox, but either one is a nuisance (and OneDrive is unreliable).
I looked at all the items with pertinent-sounding titles in the suggestions and in the similar items, but none are duplicate. A couple of them are related but aren't quite duplicate and certainly don't help.