Wash and dry your apple. 

Using a mandolin or a sharp knife, cut your apple into ⅛ inch slices. 

Lay your apple slices into your air fryer basket. Sprinkle with cinnamon. 

Place your basket in the air fryer and set the temperature to 360 degrees. Air Fry for 8-12 minutes, flipping at the 5 minute mark. Your smaller slices may come out before the larger slices; you just need to keep an eye on them. Once they are done cooking, let them sit in the basket for 5 minutes (place any you may have taken out back in) this will help them crisp up more.