To add screenshots to your presentation, there are two methods you can use, print screen, and the snipping tool.

Print screen is a key on your keyboard that allows you to take full screenshots of all connected screens.

This is good for capturing several images at once. However, if you want to remove sections, you will need to use the cropping tool in PowerPoint.

The shortcut for this is the Windows key and the print screen key.

The snipping tool allows you to capture an image of a specific section of your screen and paste it into your presentation.

Using this method, you capture only what you want to emphasize in your presentation, and typically no further cropping or editing would be required.

The shortcut for this is shift Windows Key S.

Once you've done either of these methods, a small sample of the screenshot will appear in the bottom right hand corner of your screen.

Once this appears, you can then press Ctrl V to paste the screenshot into your slide.

From here, you can edit the screenshot the same way you'd edit any other image, including cropping, scaling effects, and any of the other formatting techniques provided in PowerPoint.