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.
Those are ActiveX text boxes, which you can insert from the Developer tab. If that tab is not already visible, make it so by choosing File>Options>Customize Ribbon and checking the box beside Developer in the right-hand list of Main Tabs.
After inserting text boxes on both slides, go to the one where you want to be entering the text. Right-click on it and choose View Code. The Visual Basic Editor window will open with a macro stub called Private Sub TextBox1_Change(). Add to that macro to make it look like this:
Private Sub TextBox1_Change()
ActivePresentation.Slides(2).Shapes("TextBox1").OLEFormat.Object.Text = ActivePresentation.Slides(1).Shapes("TextBox1").OLEFormat.Object.Text
End Sub
Revise the slide numbers to suit your presentation.