transfer pdfs in ibooks to PC

here’s how I do the same .

First open the iBooks app , toggle at the 3 small dots , press share , then press save to files , there you can save it the existing folders like GarageBand etc or you can create your own folder . Note - save the file in the iPad and not in the iCloud Drive . I suggest you save it in the GarageBand folder - makes the whole process easier . Then - open iTunes connect your iPad , open the GarageBand folder , you can see the required files there . Even the third party apps like Ease US Mobimover and Dropbox can detect the files . Let me know if you still have any doubts .

Note : the GarageBand folder is found in the file sharing section in iTunes .

Hope this helps