Sub AddRow()
    Dim thisDoc As Document
    Set thisDoc = ActiveDocument
    Dim oTable As Table
    Dim oCell As Cell
    Dim oPrevRow As Row, oNewRow As Row
    Dim tmp
    'Unprotect Document
    If thisDoc.ProtectionType <> wdNoProtection Then
        thisDoc.Unprotect
    End If
   
    tmp = Selection.Text
    If tmp <> "nn" Then
        If tmp <> "n" Then
        'Selection.FormFields(1).TextInput.Clear
            ' Copy last row
            Set oTable = thisDoc.Tables(10)
            Set oPrevRow = oTable.Rows(oTable.Rows.Count)
            oPrevRow.Range.Copy
            Set oNewRow = oTable.Rows(oTable.Rows.Count)
            ' Copy last row to new row
            oNewRow.Range.Paste
           
        End If
    End If
    'Protect Document
    If thisDoc.ProtectionType = wdNoProtection Then
        thisDoc.Protect wdAllowOnlyFormFields, NoReset:=True
    End If
End Sub

I also would like to ensure that the formfields in the new row are reset to their default values without resetting the entire form.