Exporting/copying data from Excel to PDF format can be done in various ways. You can install an add-in released by Microsoft or use a 3rd party application which installs a virtual printer where you can print your data in PDF digital format. You can try these solutions based on the version of your Office package:
Office 2003 and prior: The best and easiest way to export/copy the data is to install CutePDF Writer (it’s a virtual printer which gives you the possibility to export/print/copy to PDF). Install CutePDF Writer and while the document is open select "Print" and from printer's list choose "CutePDF".
Office 2007 and above: Microsoft released an add-in which allows you to save your document in PDF. From the main menu use Save As > Other Format > Select PDF from the drop down list with file formats.