Overlays
Overlay a Rectangle, Image or Text on top of a layer
Resources
Let's Add An Overlay Modifier

The Overlay modifier is almost identical to the Background modifier, except that it adds our Rectangle, Image or Text on top of our layer, instead of behind.
A common use for Overlay would be to add a Rectangle or Image Overlay, and then add an Opacity modifier to your added Overlay
Both Background and Overlay end up creating what behaves exactly like a ZStack. For example if you had a Background Rectangle to a Text layer, this is the exact same as adding a ZStack and nesting both a Text layer and a Rectangle underneath it.