Is there a way to add a note icon at the end of a verse or after a certain word?
Yes. Here's how you would attach a Note to a word, using the desktop app.
Selection (attach the note to the highlighted text.) Reference (attach the note to the verse(s).
Officially no, but on may select the first character to the right of where you want the note to appear and attach the note to it and the icon will appear where you want. I would not advise this, however, as you lose some functions unless you also add an anchor to the text actually commented on. A better approach is to request this option be added. Make the request through Roadmap | Faithlife