This is a basic recipe for the popular Indian Raita sauce.
It is basically a yogurt sauce which traditionally is only flavoured with cumin, coriander seeds and garnished with herbs (coriander and parsley). However as with everything there are so many versions of this sauce that you can choose to make according to what you are serving it with and the amount of heat you like your food to have. So you can add chopped chilies for that. However, because yogurt is a great heat suppressor, most people who are not used to hot spicy food, the yogurt will help cool things down, in which case you might want to keep the chilies out.
Chopped or sliced red onion is another popular addition to raita, and some add shredded carrots, cucumbers and spring onions or a mix of all. Feel free to make the Raita you prefer, this here is the basic recipe without which no Raita is rightfully one!