In the instant pot on SAUTE mode, add beef, bell pepper, onion, and garlic. Saute until meat is browned and vegetables are tender.
Pour in tomato sauce and stewed tomatoes. Add salt and pepper. Set to HIGH PRESSURE for 10 minutes. Let natural release.
To cook pasta in Instant Pot, add it to the sauce and put on Saute mode until the pasta is cooked, stirring frequently. Add additional water if mixture becomes too thick.
To cook pasta not in the instant pot just cook on stove as package directs, then stir into finished dish.