Hi Stephen,
Thanks for your inquiry. You can achieve table’s border setting like this:
Document doc = new Document(MyDir + "Table.EmptyTable.doc");
Table table = (Table) doc.GetChild(NodeType.Table, 0, true);
// Clear any existing borders from the table.
table.ClearBorders();
// Set a green border around and inside the table.
table.SetBorders(LineStyle.Single, 1.5, Color.Green);
doc.Save(MyDir + "Table.SetAllBorders Out.doc");
Follow up the link for further details:
https://reference.aspose.com/words/net/aspose.words.tables/table/setborders/