Thanks for your inquiry. You can achieve your requirements using Aspose.Words. Aspose.Words for .NET is a class library that enables your applications to perform a great range of document processing tasks. Aspose.Words supports DOC, DOCX, RTF, HTML, OpenDocument, PDF, XPS, EPUB and other formats. With Aspose.Words you can generate, modify, convert, render and print documents without utilizing Microsoft Word®.
I suggest you please read following documentation links to create, modify document and apply formatting to contents of document.
Moreover, I suggest you please read about mail merge to populate with data from the data source from here:
Please also read about mail merge with regions from here:
Hope this answers your query. Please let us know if you have any more queries.