To read a Word file on the company's SharePoint using a C# program, you can use the SharePoint Client Side Object Model (CSOM) and the Open XML SDK. The CSOM can be used to access SharePoint using the ClientContext class and set up a username and password with a SecureString class and the Open XML SDK can be used to read and manipulate the contents of the Word file.
It is possible to save a Word document as an HTML web page in SharePoint, but this may not be the best option if you want the end user to be able to edit the document. Instead, you can use the CSOM to download the Word file and then use the Open XML SDK to read and manipulate the contents of the file.
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