To get a range of page numbers, you'd have to enclose the range in a bookmark and then add the \r switch, followed by the bookmark name, to the index entry XE field. Similarly, to specify that an entry should be bold, add the \b switch to the XE (index entry) field. To see all index entries in the document, show hidden text (for example by clicking the ¶ button on the Home tab to show/hide nonprinting marks). Update the INDEX field when you have made the changes.

__________________
Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional