The undo feature on Google solitaire (https://googlsolitaire.com/) allows you to reverse your last move if you make a mistake or want to try a different strategy. While playing, look for the Undo button, usually located near the top of the game interface. Clicking it will take back your most recent move, letting you adjust your sequence or correct an error. This is especially helpful when you're learning the game or planning multiple moves ahead. You can use it multiple times in a row, making it easier to experiment with different strategies without starting over completely.