You can add whatever toppings you like!
Pizza or marinara sauce
Onion and green pepper (pre chopped)
Skillet (pictured above) or foil
Spread the sauce on the pita bread, sprinkle it with cheese, and add the toppings. If the weather is cold, you can pre warm the toppings in a pan before adding them to the pizza. Ideally, cook it in a skillet covered in foil over the fire (if you don’t have a skillet, you could put it on some foil). You can also use a stove to cook it in a skillet, but it is more difficult to avoid burning the bottom before the cheese melts. Do not recommend. However you do it, just cook it until everything is warm and melted.