Insight supports the following chart styles - Line, Area, Bar, Pie & Donut.
In order to change the default styles of charts, follow the below procedure.
1. Click the 3 dots at the top right corner of the chart and click Edit element.
2. Go to Style tab, and select the desired Chart Type from the drop-down list.
The chart on the left will change as per the selected style.
3. Click Apply in the above image to save he modified chart style.