PDF (Portable Document Format) is a versatile electronic document format. It was initiated by Adobe and was originally intended for electronic presentation of printed materials. Hence, the tasks of this format follow - storing information about the color scheme and the arrangement of elements, as well as ensuring identical output on different monitors and printers. PDF documents can be opened using the free version of Adobe Reader or a web plug-in that is available for most Internet browsers. In some browsers, in particular, in Google Chrome, this format is supported even without the plugin installed. You can edit PDF files using the paid version of Adobe Reader. Also, there are a huge number of programs for both opening and working with this format, and for converting to other formats.
XLS, or Extended Cells, is the format in which tables are stored if the information is filled in Excel, which is part of Microsoft Office 2003. Now users work in Microsoft Office 2007, 2010 and 2016, in which tabular information is stored in XLSX format. When you save an Excel 2013 workbook, it is saved in the .xlsx format by default. Excel 2013 supports saving in other formats, but when you save a workbook in a different format, some of its formatting, data, and functionality may not be saved. Nowadays there are programs that quickly open such extensions. Install them on your device to be able to work comfortably. XLS files store data in rows and columns of a table with support for rich text, images, charts, and more. Macro-enabled Microsoft Excel files use the XLSM file extension.