Bookmarks and Notes are a great way to organize previously read material and take useful notes.
We have redesigned our Bookmark and Notes to Library just recently. Now, you can bookmark ayahs to your own Collections, keep track of the recitation progress using Pins and take Notes for each ayah from the Tafsir view.
This article mentions each feature of the redesigned Library in detail.
We hope this was helpful, and you find this feature beneficial.