Use the Slide Master view in Microsoft PowerPoint to customize the look and feel of your slides and create a consistent view for your presentation. You may wish to create multiple master slides ...

Launch a new, blank PowerPoint presentation for the basis of your template. Click "View" and then select "Slide Master" from the Master Views section.

Guide to change the formatting of the complete PowerPoint Presentation. Instead of changing one by one, you can apply to all of the slides in one go.