// For complete examples and data files, please go to https://github.com/groupdocs-watermark/GroupDocs.Watermark-for-.NET
using (CellsDocument doc = Document.Load<CellsDocument>(Utilities.MapSourceFilePath (FilePath)))
{
// Remove shape by index
doc.Worksheets[0].Shapes.RemoveAt(0);
// Remove shape by reference
doc.Worksheets[0].Shapes.Remove(doc.Worksheets[0].Shapes[0]);
doc.Save();
}