The optimum approach is to use content controls to accept the data as they are much more robust than bookmarks. For a text content control the following can be used to write a value from your userform to the appropriate control. Where there is no datato write to a control set the strValue to
ChrW(8203) i.e. a zero length space.
Code:
Public Sub FillCC(strCCTitle As String, strValue As String)
Dim CCtoFillRng As Range
Set CCtoFillRng = ActiveDocument.SelectContentControlsByTitle(strCCTitle).Item(1).Range
CCtoFillRng.Text = strValue
lbl_Exit:
Set CCtoFillRng = Nothing
Exit Sub
End Sub