DateAndTime Property
Returns a HeaderFooter object that represents the date and time item that appears in the lower-left corner of a slide or in the upper-right corner of a notes page, handout, or outline. Read-only.
Example
This example sets the date and time format for the slide master in the active presentation. This setting will apply to all slides that are based on this master.
Set myPres = Application.ActivePresentation
With myPres.SlideMaster.HeadersFooters.DateAndTime
.Format = ppDateTimeMdyy
.UseFormat = True
End With