itunes/cloud backing up of ibooks and voice memos etc

[maru409]

hello
new to the apple universe and trying to learn particulars

i have an iphone SE and backup both via itunes and usb cable to my PC as well as via icloud.
i store PDF files to ibooks, use notes and voice memos a lot.

in itunes on my pc after i backup ....
i see no evidence of any pdf files saved in ibooks
i see no evidence of notes
only half of my voice memos show up

in icloud when i log on via icloud.com ......
i see no evidence of ibooks or any saved PDF files (backup setting is on in phone)
i see no evidence of voice memos (no backup setting for this in phone)
i do see the notes icon however

as a new apple user i find itunes very confusing and frustrating
any advice will be appreciated

thanks