Installing and Purchasing MS Office 2013 (or later) for Terminal Server

We need MS excel (MS office 2013 or later) on our terminal server (Windows Server 2012 RC2 or Windows Server 2019 ) to process .xlsb, .xlsm, .xlsx files through c# code.

Use case is that multiple users will use web based ui to upload excel files and our backend service will extract data from files and generate report which users can view on their browser. We have already evaluated Open XML and sharepoint services but they do not seem to work in our case.

Can you please help us out in getting required licenses and providing installation information for doing so.

Thanks.