I usually keep frozen ones (chili cheese) from the store that I toss in the air fryer for lazy lunches.
Otherwise, the fun is you really just roll up whatever you please in a tortilla. I will usually use leftover roast chicken shredded up, corn, rice, black beans, and cheese. Warming the tortilla helps you fold it up without it tearing.
It's like a sandwich, both in function and construction. They're dry on the outside and sealed so it's portable and a self-contained meal. Also like the sandwich, you can use a recipe, but the fun is getting all the ingredients and their proportions toy our exact tastes.
If you do want a basic recipe and to see how everything is assembled, this is a really simple video showing construction of a slightly dressed up bean burrito.
You can also put them in a baking dish, pour enchilada sauce on top, and you have enchiladas instead if you want something saucy.