Change the font of all text in your presentation
Problem
You open a presentation file and find that whoever created it (one might say "committed it") has used way more fonts than your more highly developed design sense can bear.
Changing all of the text in the presentation, bit by bit, could be incredibly tedious, so before you tackle it, read on.
Solution
A little VBA can do most of the job for you. The code below will change the text in most or all of the PowerPoint shapes in your presentation (though it won't affect text in charts, inserted objects and some other PPT bits and pieces). You'll also have to manually change the text on your masters and layouts. But you'd have to change those anyway and at least this'll do most of the work for you in seconds:
Sub TextFonts() Dim oSl As Slide Dim oSh As Shape Dim sFontName As String ' Edit this as needed: sFontName = "Times New Roman" With ActivePresentation For Each oSl In .Slides For Each oSh In oSl.Shapes With oSh If .HasTextFrame Then If .TextFrame.HasText Then .TextFrame.TextRange.Font.Name = sFontName End If End If End With Next Next End With End Sub
See How do I use VBA code in PowerPoint? to learn how to use this example code.