Sub MergeDocs()
Dim rng As Range
Dim MainDoc As Document
Dim strFile As String, strFolder As String
With Application.FileDialog(msoFileDialogFolderPicker)
.Title = "Pick folder"
.AllowMultiSelect = False
If .Show Then
strFolder = .SelectedItems(1) & Application.PathSeparator
Els
Exit Sub
End If
End With
Set MainDoc = Documents.Add
strFile = Dir$(strFolder & "*.doc") ' can change to .docx
Do Until strFile = ""
Set rng = MainDoc.Range
rng.Collapse wdCollapseEnd
rng.InsertFile strFolder & strFile
strFile = Dir$()
Loop
MsgBox ("Files are merged")
lbl_Exit:
Exit Sub
End Sub