1. Load base drawing/photo.
2. Create a new layer on top and fill with a colour you want your "paper" edge to be.
3. Using a soft edge brush, set it on erase and create random shapes.
4. Merge top layer to photo.
5. Select fill and set to erase.
6. Erase colour, leaving shapes.
7. In Sketchclub, how much of a "paper" edge remains depend on how sensitive you set your fill function.
Once I created several sheets of shapes, I imported them into Procreate. Procreate now has a selection tool so you can select specific shapes. You can cut & paste and move the shapes where ever you want.
The picture was then imported to the Glaze app for a painterly effect but this could be easily achieved in Procreate or Sketchclub using Smudge.
Picture was then imported back to Sketchclub for the pen sketch.