Dance instruction is generally taught in one of 4 ways: series classes, workshops, private lessons and choreography.
Series classes are typically targeted towards beginners. They are typically the least expensive form of instruction on a $/hr basis, usually aimed at complete beginners. As the name implies, these classes are typically progressive in nature - one class builing on the material from the previous class. Many studios and instructors offer a set of series classes, often called something like “level 1”, “level 2”, etc. where each series builds on the previous series.
Workshops typically cost about the same or slightly more than series classes, and typically are targeted towards intermediate dancers. This is almost necessarily true due to the economics of the situation. The most common type of dancer is the complete beginner. As one goes higher in skill level, there are fewer and fewer people at that skill level. In order to get enough people in the class, instructors typically try to appeal to dancers who are just past the stage of taking series classes.
In some special circumstances (e.g. conventions) there are enough advanced dancers that it can make economic sense to do leveled workshops.
All sorts of people take private lessons from instructors, but the impression I get is that private lessons have a reputation that they are for more advanced dancers. My experience is that people who take / teach private lessons tend to focus more on fundamentals and shy away from moves.
I haven’t done much so I can’t say much about this. There are broadly two types of choreography that people do: solo and group. Solo choreography is usually one or two people who do the choreography together. If it is a pair of people they will often substantially dance together. Often the people who create the choreography are not the same as the performers. Group choreography is usually done as part of a troupe, although it can also be done as a workshop. The instructors will often dance as part of the group.