To generate a standard index that displays page numbers in a variety of ways:
Create one or more custom marker types, and name them
in a way that indicates their intended use. For example, if you
want to distinguish index entries that refer to footnotes, you might
create a marker type called IndexNote.
Index your source document, using the Index marker type for regular entries and your custom marker types for the others.
Generate the index. Select the Index marker type along with the custom ones.
In the index, edit the special text flow
on the reference page for the custom marker (the reference page
would be called IX) to add text after the page number or to change
character style. For example, you might change the text for IndexNoteIX as
follows to have [note] appear after the page number: <$pagenum>
[note].
Update the index again for your edits to take effect.