Peel the sweet potato and cut into the shape of fries (I first cut it into thin rounds, then cut each round into thin strips).
Put raw sweet potato fries in a bowl, pour olive oil over them and toss with your hands until fries are coated with oil.
Put the sweet potato fries in the air fryer basket in a single layer. Cook at 400F for 15 minutes, shaking the basket halfway through. Check the fries for doneness, if they are not ready cook for an additional 5 minutes.
Put sweet potato fries on a serving plate and sprinkle with salt and pepper to taste.