In versions of PowerPoint earlier than Microsoft Office PowerPoint 2007, you applied a design template to change the look of your presentation. In Office PowerPoint 2007 and later, if you want to change elements such as the types and sizes of bullets, background design and fill colors, and placeholder sizes and positions, you apply a theme to achieve the same result.
Presentations are often started with templates, which are slides or sets of slides that act as a pattern or blueprint and contain layouts, theme colors, theme fonts, theme effects, background styles. Themes, which affect the look of a presentation, can be applied to a presentation at any time and provide coordinating colors, a matching background, fonts, and effects. To learn more, see Understand the difference between PowerPoint templates and themes.