When the display reads HOT, add the oil. Add the ground beef to the pot and cook for 3 minutes. Add the onion and continue cooking until the onion is softened. Add the bell pepper and continue to cook, stirring, until the beef is no longer pink. Carefully drain and discard excess fat.
Toss the beef mixture with the taco seasoning and add the water. Scrape up any browned bits in the bottom of the pot.
Lock the lid in place and turn the valve to the sealing position. Select pressure cook or manual, high pressure, and set the time for 5 minutes.
When the time is up, carefully turn the valve to the venting position (quick release).
To reduce the liquids, choose the sauté function and cook, uncovered, for 2 to 3 minutes.
Serve the taco meat in taco shells or on salad greens with your favorite toppings.
For burritos, assemble warmed flour tortillas with heated refried beans, taco meat, and cheese. Fold over the ends of the tortillas and then roll them up to encase the filling. Serve them with your choice of garnishes and sauces.