How to Add Themes to PowerPointby Laura Gittins
By default, PowerPoint presentations consist of white slides with black text. PowerPoint themes add style. PowerPoint has several built-in themes included when you install the Microsoft Office package, but you may also download new themes from the Microsoft Office website and add them to presentations through PowerPoint itself. When you add a theme to a presentation, PowerPoint changes any or all of the colors, fonts layout, shapes, tables and graphics. You may then customize these effects to get the perfect theme for your presentation.
Open a PowerPoint presentation. Click on the "Design" tab.
Click the "More" button in the "Themes" section. Click "More Themes on Microsoft Office Online." This opens the "Office Document Themes" page in a Web browser.
Browse through the available themes and click the one you want. Click the "Download" button on the next page and save the file to your computer. Right-click on the downloaded file and extract its contents.
Restore your PowerPoint presentation. Click the "More" button again and click "Browse for Themes." Navigate to the theme you extracted and double-click on it. This applies the theme to your presentation.