Heat a skillet over medium heat
Add ground beef, turkey, chicken, or plant-based crumbles
Cook until browned and fully cooked
Drain excess fat if needed
Add taco seasoning
Add water according to the seasoning packet or about 1/4 to 1/2 cup
Stir well to combine
Simmer until the sauce thickens
Warm taco shells or tortillas
Fill shells or tortillas with the seasoned meat
Add shredded lettuce
Add diced tomatoes
Add shredded cheese
Add salsa
Add sour cream if desired
Add chopped onions if desired
Add avocado or guacamole if desired
Serve immediately