Select the slide objects you want to align. (To select multiple objects, press and hold down the Ctrl key on your keyboard as you click each object.)
Click the Draw button on the Drawing toolbar, select Align or Distribute , and then click an alignment.
PowerPoint aligns the objects.
If your slide contains two or more illustrations, you might need to align them to improve your slide's appearance. To do so, use the alignment commands on the Draw menu to align selected objects on a slide; you can choose to align objects horizontally or vertically on the slide.
Use the Distribute options on the Draw menu to space your objects evenly on the slide in a vertical or horizontal manner.