Here's something I make often. Sometimes I'll use a tortilla instead, it just depends what I have on hand. You can use any kind of cheese you like and if you're in the mood, add other toppings. I like the little bit of sourness you get from using tomato paste but you could use pizza sauce if you prefer.
1 tablespoon tomato paste
1/2 teaspoon oregano
1/2 teaspoon granulated garlic
shredded or sliced mozzarella cheese
Preheat oven to 450F.
Spread the tomato paste over the pita then sprinkle with oregano and garlic. Top with cheese. Place directly on the oven rack and bake for about 10 minutes or until the cheese is bubbly.
Tip: Make sure your cheese isn't too close to the edge or it could bubble over and make a mess of your oven. You can place your pizza on a baking sheet or foil if you want to play it safe but sometimes the bottom doesn't get crispy.