Archiving a board will store a board layout settings for later but it will not be shown under available board list. You can Un-Archive a board, if you want to reuse it later. A board layout cannot be archived if it is used by an archived project or a deleted project that is still recoverable through recycle bin.

Note: Archiving a board needs “Board Configurations” rights handled under Global permissions.
Note: Default Layout cannot be deleted. The delete option is shown only for custom board layouts.