The Soft Edges effect adds an eaten-up, feathered edge to a selected shape. PowerPoint does provide you with some ready-to-use pre-set Soft Edges, but you may want to edit the applied Soft Edges effect to be less or more pronounced.
To learn more, choose your version of PowerPoint. If we do not have a tutorial for your version of PowerPoint, explore the version closest to the one you use.
Microsoft Windows
Advanced Soft Edge Options in PowerPoint 2016
Advanced Soft-Edge Options in PowerPoint 2013
Advanced Soft-Edge Options in PowerPoint 2010
Tutorial Code: 08 03 11
Previous: 08 03 10 Apply Soft Edges to Shapes in PowerPoint
Next: 08 03 12 Apply Bevel Effects to Shapes in PowerPoint