Indexes.Format (Word)

Returns or sets a WdIndexFormat that represents the formatting for the indexes in the specified document.

Possible Values are wdIndexBulleted - Bulleted, wdIndexClassic - Classic, wdIndexFancy - Fancy, wdIndexFormal - Formal, wdIndexModern - Modern, wdIndexSimple - Simple, wdIndexTemplate - From template.
ActiveDocument.Indexes.Format = wdIndexBulleted