A some code to Select a Folder and then use the variable that the selection is stored as instead of a static Folderpath...
Private Sub CommandButton1_Click()
Dim z, x, i As Long, ii As Long, fldr As FileDialog, SelFold As String
Set fldr = Application.FileDialog(msoFileDialogFolderPicker)
With fldr
.Title = "Select a Folder"
If .Show <> -1 Then Exit Sub
SelFold = .SelectedItems(1)
End With
x = [A1:c100]
ReDim z(1 To UBound(x))
For i = LBound(x) To UBound(x)
For ii = LBound(x, 2) To UBound(x, 2)
z(i) = z(i) & x(i, ii)
Next ii
Next i
CreateObject("scripting.filesystemobject").CreateTextFile(SelFold & "\Saida.txt").write Join(z, vbCrLf)
End Sub