Tomato sauce is tomato cooked longer and thicker than passata, sometimes already flavoured with a soffritto or herbs. It is ready to use and gives body to dishes in minutes.
I use it as the base for lasagna, in quick pasta sauces, on oven-baked vegetables such as fennel gratin, and as a "mirror" sauce to serve rolls and fritters on. Homemade at the end of summer with ripe tomatoes, it brings summer to the pantry all winter long.