The main feature of a board is Columns. You can have as many or as few as you want and they can represent a lot of different things: categories, workflow steps, pipeline stages or people. You will find an example on using boards for categories and workflow steps here.
In a board, you can add new columns and re-order them. If you click on a column name, you get the above menu. Here you can subscribe to a column, rename it, archive all the cards within the column or delete it entirely.