Doing this reveals more of whatever is layered behind the shape.
Can You Change the Transparency of Shapes in PowerPoint?
Shape transparency is supported in most versions of PowerPoint.

You have complete control over this percentage level.
By default, the shapes have a solid fill color which blocks out whatever is under them.
Transparency is how you make whatever is behind the shape become more visible.

How Do You Make a Shape Transparent in PowerPoint?
Right-grab the shape, and chooseFormat Shape.
Expand theFillmenu from the newly opened slide-out menu on the right.

Enter a value into theTransparencymenu, or use the slider to adjust it manually.
It’s simple: useNo fill.
With this one option, the shape becomes completely see-through.

It retains the outline, so the overall shape isn’t completely invisible.
From the Format Shape menu, move the Transparency slider to make the image nearly or fully transparent.
Tomake an image background transparent in PowerPoint, remove the background to add transparency.
SelectPicture Format>Remove Background.