Preheat your oven to 350°F (175°C).
In a medium mixing bowl, combine the softened cream cheese, shredded cheddar cheese, shredded mozzarella cheese, sour cream, and mayonnaise. Mix well until smooth and creamy.
Add the garlic powder, onion powder, paprika, black pepper, and salt to the cheese mixture. Stir until all ingredients are well combined.
If using, fold in the chopped green onions for added flavor and color.
Transfer the cheese mixture to a baking dish and spread it evenly.
Bake in the preheated oven for 20-25 minutes, or until the dip is bubbly and golden on top.
Remove from the oven and let it cool for a few minutes before serving with pretzel bites or pretzel chips.