All about boards in iOS
Adding a board
You can add a new board by selecting the + (plus sign) from the top right corner of your boards list page.
Name your new board, select which organization it belongs to (if applicable) and choose the visibility settings for the board, then select "Create" to create your new board.
By default all newly created boards will be set to private. You can select "Visibility" to set the visibility of your board to either private, public, or organization (if the board is associated with an organization). Please note that public boards are viewable by anyone with a link to the board and will be searchable in search engines like Google.
Changing board settings
To change your board's settings, open your board and select the "..." icon in the top right corner of your board. This will open the board's sidebar.
The board menu in iOS
From the sidebar, you can star a board (by tapping the star icon), view archived cards/lists (by tapping the file box), and change board settings (by tapping the gear icon).
Archiving a board
Due to the collaborative nature of Trello, it is not possible to delete a board. You can archive the board instead if you don’t need it anymore. This is the same closing a board in the desktop version of Trello.
To archive a board in Trello, first open the board you would like to archive. Then, open the board's sidebar ( the “...” icon in the top right of the page), and select the gear icon in the top right of the page. From there, select "Archive Board" at the bottom of the settings.
Switching between List view and Board view
When you’re viewing board, you can zoom in on a list so that it fills the whole width of the screen by tapping the list's name or the blank space underneath the list. To zoom back out to the view more of the board, tap the board background.