I may not be understanding correctly, but that is the default design of the app. If you have another device like a tablet, or if you use a web browser on a computer of a device and you'll see the notes in those other devices as well.
I often do demonstrations of the gospel Library App where I will mark the scriptures on my computer using a web browser, and then synch my gospel library app and see the mark show up on the gospel library app.
“A long habit of not thinking a thing wrong, gives it a superficial appearance of being right, and raises at first a formidable outcry in defense of custom.”
― Thomas Paine, Common Sense