Option Explicit

Private Sub btnSave_Click()
Dim oRng As Range
    If cmbColour.ListIndex >= 0 Then
        With ActiveDocument
            On Error GoTo lbl_Exit
            If .Bookmarks.Exists("My_Colour") = True Then
                Set oRng = .Bookmarks("My_Colour").Range
                oRng.Text = cmbColour.Value
                oRng.Bookmarks.Add "My_Colour"
            End If
        End With
    Else
        MsgBox "Select Colour", vbCritical
    End If
    Unload Me
lbl_Exit:
    Set oRng = Nothing
    Exit Sub
End Sub

Private Sub UserForm_Initialize()
Dim i As Integer
Dim sColour As String
    With ActiveDocument
        If .Bookmarks.Exists("My_Colour") = True Then
            sColour = .Bookmarks("My_Colour").Range.Text
        End If
    End With
    With cmbColour
        .AddItem "Red"
        .AddItem "Green"
        .AddItem "Blue"
        For i = 0 To .ListCount - 1
            If sColour = .List(i) Then
                .ListIndex = i
                Exit For
            End If
        Next i
    End With
End Sub