1. If the combobox need to fill only once when opening the workbook then you can put code in ThisWorkbook code module as below:
Code:
Option Explicit
Private Sub Workbook_Open()
With Sheet1.cboReimbMthd
.Clear
.AddItem "STD"
.AddItem "LOUwBD"
.AddItem "Model"
End With
End Sub
2. If you intend to refill the combo again later then it's better to create a Sub in Sheet1:
Code:
Option Explicit
Sub FillComboBox()
With Me.cboReimbMthd
.Clear
.AddItem "STD"
.AddItem "LOUwBD"
.AddItem "Model"
End With
End Sub
And Call it in Workbook_Open(). You should qualify the sub with the sheet codename:
Code:
Option Explicit
Private Sub Workbook_Open()
Sheet1.FillComboBox
End Sub