The Select Widget in Web App Builder allows you to draw a polygon and has a built in Export to CSV option, but not an exact Copy option.
Or is the end goal to identify Points relative to an existing Polygon feature layer in the Web Map, like the Select by Location tool in ArcGIS Pro? If so, the Query Widget allows you to filter by Spatial Relationships. These results can be viewed in the Attibute Table. If the "Allow Export to CSV" option is enabled in Attribute Table Widget, then the selected features can be Exported to CSV.