Use Backspace/Delete and Undo/Repeat
Have you ever made a mistake in your document and needed to go back and make changes, but you thought it was too late? Good news! Word offers a feature that helps prevent this from happening.
The Undo command lets you "undo" or delete the last change made to your document. As you can imagine, this is a useful feature. If you make a change or mistake you do not want or did not mean to do, you can simply "undo" your action.
Word remembers up to 300 actions in a document and allows you to undo any or all of them as long as you haven't closed the document first.
Notice the small list arrow next to the Undo button. When you click it, you'll see a list of the separate actions you have performed on the document you are working on. You can select as many actions as you want to undo.
IMPORTANT: If you undo an action in the middle of the list, you will also undo all of the actions above the one you select. For example, if you undo the 15th action in your list, you will also be undoing the 14 actions that came before the one you select.