This example adds WordArt that contains the text "Test" to myDocument
.
Set myDocument = ActivePresentation.Slides(1)
Set newWordArt = myDocument.Shapes _
.AddTextEffect(PresetTextEffect:=msoTextEffect1, _
Text:="Test", FontName:="Arial Black", FontSize:=36, _
FontBold:=False, FontItalic:=False, Left:=10, Top:=10)