Do you want to add a slide that contains the content of an existing slide in your presentation? It’s easy to duplicate your slides. Here’s how.
In Normal view, select the slide thumbnails of one or more slides that you want to duplicate. To select multiple slides, click a slide thumbnail, and then press and hold CTRL while you click the other slide thumbnails.
On the Home tab, in the Slides group, click the arrow next to New Slide, and then click Duplicate Selected Slides.
The duplicated slides are inserted directly underneath the lowermost slide that you selected.