Undo and Redo buttons are available in the board menu in the upper left corner of the board. You can Undo and Redo up to 30 actions in Miro during the current session. If you refresh the page or re-open your board, Undo and Redo commands will be unavailable.
To undo your previous actions, press Ctrl+Z until you reach the action you want to undo. If you prefer mouse navigation to keyboard shortcuts, click Undo at the top of the board.
To redo an action you've undone, press Ctrl+Shift+Z or click Redo at the top of the board.
Both the Redo and Undo buttons appear in the menu only after at least one action on the board. You can undo/redo only your actions, not your collaborators'.