Sub SO()

Dim lastRow As Long
Dim ws1 As Worksheet
Dim ws2 As Worksheet

Set ws1 = Workbooks("Workbook1.xlsm").Worksheets("Orderheader")
Set ws2 = Workbooks("Workbook2.xlsm").Worksheets("Sheet1")

lastRow = ws1.Cells(ws1.Rows.Count, "A").End(xlUp).Row

ws1.Range(Cells(2, 1), Cells(lastRow, 1)).Copy

ws2.Range("A2").PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _ :=False, Transpose:=False

End Sub