-Entering text directly into the PDF document
Add text to document (Windows)
-Bookmark features (Is this working and how)
currently we support adding bookmarks to the TOC (without UI). IS that what you want, or you want to save bookmarks in database?
This is currently not available, if you need this feature you need to contact sales department.
We do not support Xamarin UWP, so unfortunately we do not have any sample code to help you in this.