Here are a couple important things to know before you delete a board:
Deleting a board is permanent—you cannot restore it. If you may need to access the board at a later time, we recommend archiving instead.
Only the owner of a given board can delete that board, unless the board belongs to an Enterprise account. If you are part of an Enterprise plan, check out this article to see who can delete boards: Enterprise roles and permissions
Deleting a board
To delete a board:
Sign in to your account and navigate to the Projects page.
Click the Boards tab.
Hover over the board you want to delete and click the ••• (more) icon.