Preheat your oven to 200°C (google °F). Cut the right size of baking paper for your tray.
Take your flour/wheat tortillas and place them on the tray with baking parchment on it. Use as much tortillas as you wish, the written serving size is what I usually make for myself if I use the smaller ones (I forgot the exact size sorry).
Put ketchup on them as much as you like and use a spoon to spread on it equally. You can also use tomato sauce as a substitute for ketchup (warning: do not go heavy with the sauce as the tortilla may get too wet and makes it difficult to role and longer to bake). You can use both too.
Take your cheese and likewise spread it on the tortillas equally like the ketchup with your fingers. I personally use a store bought shredded cheese for the pizza but I don't see why not get creative with it. Add oregano or other spices maybe to taste. I've seen a recipe online where they've put salami in it too.
Once you put all your toppings on the tortilla, carefully role it and after it, lightly press it so it doesn't unroll on the tray. Wait until the oven is ready and them put them in.
Bake your pizza tortillas for about 10 minutes or at least until the cheese melts.
Take them out and rest them on the tray. Once they cool down a bit they are ready for consuming. As you can see, it's pretty easy to make and I encourage you to try putting in other toppings or sauces. Would also appreciate if you'd let me know if you tried it with other ingredients. Enjoy!