You can use keyboard shortcuts (Command-Z on Mac, Ctrl + Z on Windows) to undo recent changes that you've made to your documents.
Likewise, you can easily redo things if you change your mind (Command-Shift-Z on Mac, Ctrl + Y on Windows).
Undo can be used to reset changes or additions of images, text, formatting elements, and even Smart Tables.
You can also restore previous versions of a doc from its history if something has gone wrong with the current edit, or you can recover a deleted document from the Trash if it was mistakenly deleted.