Once you've put all the things that you want on the slide, you need to align them so they look just right.
For example, in this picture, the text box with the caption will look best once it's aligned evenly with the picture — either flush left, or correctly centered.
You use the Arrange commands to align slide elements.
To align the caption so it's flush left with the picture, first select both placeholders.
Find the Arrange
group on the Format
tab, in Picture Tools
Click the Align
button, and then click Align Left
The Arrange commands are also available in the Drawing group on the Home tab.