A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
Add this macro to your presentation (you'll need to save it as a PPSM rather than PPSX in order to preserve the macros)
Sub TextMe(oClickedShape As Shape)
Dim oSh As Shape
Dim sText As String
For Each oSh In SlideShowWindows(1).View.Slide.Shapes
If oSh.Name = oClickedShape.Name Then
Exit For
End If
Next
sText = InputBox("Type your text here", "Text. Gimme TEXT!", "")
If Len(sText) = 0 Then
Exit Sub
End If
oSh.TextFrame.TextRange.Text = sText
End Sub
For any shape whose text you want to edit during the slide show, give the shape an action setting of Run Macro and choose TextMe.
During the show, if you click on one of these shapes, you'll get an input box where you can enter the text you want and when you press OK, the shape's text will be added.
In theory, it shouldn't be necessary to check each shape on the slide and compare its name to the clicked shape's name, but this bit of Mac VBA/PPT is buggy so we have to go about it in a roundabout way.