Here is a step-by-step guide, for anyone using Procreate. A screenshot of the settings for the Monoline brush on the Caligraphy section of the Brush Library.
Firstly, open a canvas.
Prepare a white, blank photo that is cropped into a square.
Next, here are the screenshots in ascending order. Just follow the settings as illustrated.




Edit the shape source as shown below. Insert the white, blank image cropped as a square by tapping ‘edit’.

















That’s all, it should work.
Writer: s.psycho