To insert a new slide in your presentation directly after the currently selected slide, open the Insert menu and select New Slide.
PowerPoint creates a new slide with the same design as the slide that was originally displayed, adds the new slide to the Outline tab, and opens the Slide Layout task pane.
To delete a slide, right-click the slide or slide number in the Outline tab and select Delete Slide from the shortcut menu that appears.
The slide is deleted.
INTRODUCTION
If you think of a new topic you want to include in your presentation, you might need to insert a new slide. On the other hand, you might determine that your presentation runs a bit long and decide to delete a slide.
TIP
Changing the Design of New Slides
Any new slides you add will have the same design of the slide that was selected before you added the new slide. To apply a different design, first scroll through the design options in the Slide Layout task pane. When you find the design you need, double-click it to apply it.