You didn't indicate where you wanted the text to go so I'll show you how to put it in front of the anchor for the textbox.
Code:
Sub GetText()
Dim aShp As Shape, aRng As Range
If Selection.ShapeRange.Count > 0 Then
Set aShp = Selection.ShapeRange(1)
Debug.Print aShp.TextFrame.TextRange.Text
Set aRng = aShp.Anchor
aRng.Collapse Direction:=wdCollapseStart
aRng.FormattedText = aShp.TextFrame.TextRange.FormattedText
End If
End Sub