If you go into the configuration menu of your agile board(you must be the owner), and click on the columns menu item on the left, you can remove statuses from the board. Simply drag the status from the column it is in to the “unmapped status” section on the left.

The most common method is to set up issue security. Here is a link to good documentation of this feature from Atlassian. https://confluence.atlassian.com/jira/configuring-issue-level-security-185729623.html