If you have applied styles in your document, you can quickly change the formatting of all occurances of that style in your document by editing the style.
How to Edit Styles
editStylesGDocs.mp4
Editing Styles in Google Docs
editStylesWord.mp4
Editing Styles in Microsoft Word
Resources
Practice editing styles using the documents below.
To Edit the Google Docs you will need to open it and make a copy.
To Edit the Microsoft Word document you will need to download it and open in MS-Word.