What is the difference between Audi A6 models and their trim levels?

I've been looking at Audi A6 cars and I noticed they have different trim levels. Can someone explain the difference between these models and their respective trims?

The Audi A6 has several models such as the Premium, Premium Plus, and Prestige, with each model having different trim levels. Typically, the higher the trim level, the more features and upgrades you get. For example, the Prestige trim has features like a head-up display and a 16-speaker Bang & Olufsen sound system that are not available on the lower trims.