In your sprint boards now you can find a Column Options button available.
Once you click Column Options a side pane will open allowing you to customize the columns of the Sprint/Task board.
2 – You can drag and drop to reorder columns, except the first and the last columns.
3 – You can remove a column except first and the last column using delete button of each column.
4 – You can change the name of the column. It is possible to even change the column name of first and last columns as well.
5 – Select an available state to a column. It is not possible to change the state of the first or the last column.
6 – Save button can be clicked to apply the changes to the sprint/task board.