Remove the puff pastry sheets from the freezer and allow them to thaw for about 10 minutes.
Cut the puff pastry sheets into equal-sized squares.
Add the chopped red pepper, green pepper, pizza sauce and cheese to a bowl. Mix well.
Divide the pizza filling between the pastry squares, keeping the filling in the centre.
Bring the corners of each pastry square towards the centre and overlap them slightly to form an envelope-shaped pizza puff. Press gently to close.
Arrange the pizza puffs in the air fryer in a single layer, leaving a little space between them.
Air fry at 185°C / 365°F for 16-18 minutes, or until the pastry is puffed, crisp and golden brown.
Rest for a few minutes before serving, as the cheese and sauce inside will be very hot.