It is possible to export to CSV through the Attribute Table widget. The Attribute Table widget is added to a web app by default. The option must be checked under the widget's properties in edit mode. <a href="http://doc.arcgis.com/en/web-appbuilder/create-apps/widget-attribute-table.htm" target="_blank">http://doc.arcgis.com/en/web-appbuilder/create-apps/widget-attribute-table.htm</a>Once enabled, use the following steps to export to a CSV file:1. Use the Select widget to select the desired features. 2. Click the ellipsis button next to the layer and select 'View in Attribute Table'.3. In the attribute table, click the options drop-down and select 'Export Selected to CSV'.