var byteKey = Convert.FromBase64String("xxxxxx");
//注冊,實作去水印
new Aspose.Pdf.License().SetLicense(new MemoryStream(byteKey));
new Aspose.Cells.License().SetLicense(new MemoryStream(byteKey));
new Aspose.Words.License().SetLicense(new MemoryStream(byteKey));
new Aspose.Slides.License().SetLicense(new MemoryStream(byteKey));
string wordFile = "wordFile.docx";
string excelFile = "excelFile.xlsx";
string pptFile = "pptFile.pptx";
string pdfFile = "pdfFile.pdf";
Aspose.Cells.Workbook workbook = new Aspose.Cells.Workbook();
workbook.Worksheets.Add();
workbook.Worksheets[0].Cells[1, 1].Value = "excelTest";
workbook.Save(excelFile);
workbook.Save(wordFile, Aspose.Cells.SaveFormat.Docx);
workbook.Save(pptFile, Aspose.Cells.SaveFormat.Pptx);
workbook.Save(pdfFile, Aspose.Cells.SaveFormat.Pdf);
Console.WriteLine("儲存成功!");

示例代碼不包含key,下面有擷取key方法
office所有版本2003-2022,Pdf所有版本均支援。
加微信25489181,擷取key