Is it possible to create a table having a final row, with SUM of all the cells in that column.
Document document = new Document();
Table table = document.AddSection().AddTable(true);
table.ResetCells(1, 3);
table.Rows[0].Cells[0].AddParagraph().AppendText("1");
table.Rows[0].Cells[1].AddParagraph().AppendText("2");
Field field = new Field(document);
field.Code = $"=SUM(LEFT) ";
Spire.Doc.Documents.Paragraph paragraph = table.Rows[0].Cells[2].AddParagraph();
paragraph.ChildObjects.Add(field);
FieldMark end = new FieldMark(document, Spire.Doc.Documents.FieldMarkType.FieldEnd);
paragraph.ChildObjects.Add(end);
field.End = end;
document.IsUpdateFields = true;
document.SaveToFile("res.docx");