Do you have to cook bell peppers when stuffing?

I boil the whole peppers in a large pot of water for about 5 minutes. I then take them out of the water and drain. Once drained, the peppers are ready to be stuffed.

It depends a lot on what you stuff them with. Some people like to stuff them with a meatloaf mixture. Since that needs to bake for about 30 minutes, the pepper get cooked enough while the meat cooks. If your stuffing won't be cooked that long, then boiling the pepper as described above is a good idea.