Have you ever noticed how people talk differently depending on the situation or the people they are talking to? That's called their "style" or "manner of address."
For example, when you're talking to your friends, you might use more slang words or say things in a casual way. But when you're talking to your teacher or your parents, you might use more formal language and be more polite.
Different styles of address are like different sets of rules for how you should talk to people, depending on the situation. Just like how you might wear different clothes for different occasions, you use different language and tone for different situations.
Sometimes, people might have a very distinct style of address that sets them apart from others. Maybe they use really fancy or complex language all the time, or maybe they use a lot of slang words even in formal situations.
It's important to understand and be able to adapt to different styles of address, so that you can communicate effectively with all different kinds of people in all different kinds of situations.