Class Libraries & REST APIs for the developers to manipulate & process Files from Word, Excel, PowerPoint, Visio, PDF, CAD & several other categories in Web, Desktop or Mobile apps. Develop & deploy on Windows, Linux, MacOS & Android platforms....method CSV Represents a CSV file XLSX Represents an Office Open XML...OpenOffice spreadsheet file (so XLS, XLSX, XLSM, XLSB, ODS and so on)...