Pre-heat your air fryer to 350° F.
Using a small round cylinder (I use the large end of a pastry bag tip) to make holes in all of the individual biscuits on a sheet of parchment paper.
Spray your air fryer with a canola oil cooking spray to make it non-stick, then place donuts in the fry basket (as many as will fit without them touching). You can add the donut holes if they fit.
Air fry until they start to turn golden, then flip after 3 to 4 minutes. Continue to cook for another 3 to 4 minutes until they are golden on all sides and cooked through. The donut holes will take less time.
Combine the sugar and the cinnamon in a shallow bowl.
When the donuts are finished cooking, transfer to a sheet pan, then begin brushing them with the melted butter and dip to coat all sides in the cinnamon-sugar.