Do I have to cook everything?

No, most foods are served raw. Most meats, veggies and fruits just need to be chopped up. You don't even need to peel most veggies because a lot of the nutrients are in the skin.

Some meats (like chicken and turkey) should be cooked for health reasons and a few veggies like sweet potatoes and grains need to be cooked because they are hard for pets to digest raw.