Display a filtered list on your portal using the data table from instance definition widget. From the widget's context menu, portal users can export the filtered list. You can use this base system widget as-is in your portal or clone it to suit your own business needs.

After you add the data table from instance definition widget to a page, use the instance options to configure the appearance of the table.

Figure 1. Data table from instance definition widget
Data table from instance definition widget with instance option set to table=incident
Note: If you want this widget to be accessed by guest users, you must select the Public option in the widget record for both this widget and the Data Table widget.

Instance options