& "000000"
Private Sub Worksheet_Change(ByVal Target As Range)
Application.EnableEvents = False
If Target.Column = 1 Then Target = Format(Target, "00000000") & "000000"
Application.EnableEvents = True
End Sub
Sub test()
Dim c As Range
For Each c In Range("A1:A" & Range("A" & Rows.Count).End(xlUp).Row)
c.NumberFormat = "@"
c = Format(c, String(8, "0")) & String(6, "0")
Next
End Sub