The igx-autocomplete directive provides a way to enhance a text input by showing a panel of suggested options provided by the developer.
Using the igx-drop-down as a provider, allows using its functionalities like grouping, templating, etc.

You can read more about configuring those components, using the following links:

igx-autocomplete - README or the official documentation.
igx-drop-down - README or the official documentation.

The following sample demonstrates igx-drop-down with defined groups:

Town

@for (eRegion of regions | <%=camelCaseName%>RegionContains:townSelected; track eRegion) { @for (town of eRegion.towns | <%=camelCaseName%>StartsWith:townSelected; track town) { {{town.name}} } }

Postal Code: {{postalCode}}