SpaceAfter Property
Returns or sets the amount of space after the last line in each paragraph of the specified text, in points or lines. Read/write Single.
Example
This example sets the spacing after paragraphs to 6 points for the text in shape two on slide one in the active presentation.
With Application.ActivePresentation.Slides(1).Shapes(2)
With .TextFrame.TextRange.ParagraphFormat
.LineRuleAfter = False
.SpaceAfter = 6
End With
End With