How to Undo and Redo in Google Slides
You don't need to be afraid of making mistakes in Google Slides because you can use the Undo feature to erase your actions. The undo, redo, and repeat commands are very useful when working with text in a presentation.
Press Ctrl + Z.
Your last action is undone. For example, if you deleted an item and decided you wanted to keep it after all, undo would make it reappear.
The undone action is redone.
You can also use the Redo button to repeat the last action you performed.
The last action is repeated.