If you change the formatting of text or images and then decide you don't like it, you can undo it.
Select Undo to undo the last formatting change.
Clear All Formatting
Select the text with the formatting you want to clear.
Select Home > Clear All Formatting or press Ctrl + Spacebar.
If you made changes to a picture and later want to undo the changes:
Select the picture.
Select Picture Tools > Format.
Select Reset Picture.