How do I copy pdfs to iBooks

Your question is somewhat vague. You want to sync pdf files from the Mac to your iPad, is that correct? How did you just "copy" them to the iPad in the past? What is not working about that process now? You can still sync them to the iPad using iTunes, but you have to import the PDFs into the iBooks app on the Mac first.

Here is how I do it for PDF files. Install the Adobe Acrobat App if you don't have it already in your iPad. You can get it from the App Store for free. After it is installed, connect your iPad to your Mac and open iTunes. Select the iPad and under Apps you will see Adobe Acrobat. Select it and the "add file". Copy all the PDFs you want, from your Mac and then sync your iPad. The PDFs will appear in your Adobe Acrobat App. You can also try Airdrop to transfer the files to the App but I recommend the above.

Read this support article about syncing and saving PDFs to iOS devices. You have to either import the PDFs into iBooks or drag and drop the files into the iBooks app on the Mac first and then select the files to sync to your iPad using iTunes.

iBooks: Viewing, syncing, saving, and printing PDFs on iPhone, iPad, and iPod touch - Apple Support

The suggestion posted by elcpu is a very good suggestion as well. He uses Adobe Acrobat and iOS file sharing in order to move the PDFs from his Mac to the iPad. This talks about using file sharing.

About File Sharing on iPhone, iPad, and iPod touch - Apple Support

I second elcpu's recommendation of Adobe Acrobat. It is a much more robust app that iBooks and it is free. You might want to take a look at it.

Thank you Demo.... Adobe Acrobat works well for me. 🙂

I Think that we need a little clarification again. Are you talking about not being able to see your music in the iPad or in iTunes on the iMac?

I don't use Apple Music at all, and I haven't updated to the very latest iTunes on my Mac because I really don't need the Apple Music features. I imagine at some point I will be forced to upgrade, but I think I will wait until that time - when I have to do it,

I am confused as well... I do have the latest iTunes (on both my rMBP and a Dell PC) but I don't have any problems with either. I can see my music, etc. on both. IMO I don't think this is a bug with Apple Music. As Demo asked, can you be more specific as to your problem? The more details the better. Hopefully one of us can help you then.