Clipping masks are a deconstructive way to manipulate your layers. The bottom layer defines the visual boundaries of the layers you apply the mask to.
To start off, I created a black circle. I then added some teal blobs on top. I made sure some of the blobs went out past the circle, to show you what the mask will do.
Once I’m done, I’m going to tap on the layers panel and then select my layer. With the menu that pops out I’m going to hit ‘clipping mask’
You can see that instantly the teal layer is confined to the circle. But the great thing is I didn’t have to manually erase anything AND the layer is sill in tact - meaning if I need to edit or redo anything in the teal layer I don’t have to start over.
You can add more layers, and each time you will need to click on Clipping Mask. You’ll know it’s being masked when you see the arrow next to the layer icon.
Here is the final product! Clipping masks can save so much time, and I love utilizing them in Procreate! Another bonus to this method is that when you export it as a PNG it will only show the circle shape since the rest is being masked - it won’t show the parts of the layers that extend past the circle.