In Microsoft PowerPoint in order to see all slides on one screen use

• view, slide sorter

• view, slide

• view, master

• view, slide show

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Explanation: If you want to see all the slides together on one screen, you can use MS PowerPoint's View, Slide Sorter feature, which you'll find at the bottom right of PowerPoint.You can also refer to the image below for a better understanding.
With this feature, we can view and change the slide layout. Also, we can add and delete slides. This view helps us quickly and easily check the design of entire slides at once.

Slide, Sorter View