PDF attachments

HI

I use each textbook chapter as a pdf and attach to my chapter notes. This works well on the original computer i use, but the pdf is not visible on the laptop remotely (the highlights do carry over, and the pdf is visible when using the web browser)

My question is:
Where is the pdf stored? Is it only local linking?
Can the original pdf be in a protective onedrive cloud service?

Thanks
Akesh

The use of cloud services is a crucial one
+1

As per the storage of the PDF, it seems its only locally, but I’m new as well.