Thanks for your question.
You can use Aspose.Cells for .NET to convert your Excel files into Pdf. Please see the code below, it opens a source workbook and convert it to pdf. I have attached both the source and output pdf.
Also I have attached a screenshot.
You should also see Aspose.Cells for .NET Documentation and Live Demos.
string path = @“F:\Shak-Data-RW\Downloads\source.xlsx”;
Workbook workbook = new Workbook(path);
workbook.Save(path + “.out.pdf”, SaveFormat.Pdf);