Reports in XML format (TRDX files) can be loaded in viewer and exported from there, or exported on the server with the ReportProcessor - Exporting Report Programmatically
In the example is used a TypeReportSource to pass the report to the ReportProcessor, where for TRDX files you can use UriReportSource or XmlReportSource. If the report template must be modified before exporting it, you can deserialize the XML
and use an InstanceReportSource. For more details check Report Sources
The way reports will be rendered and the available settings for each renderer are available in the corresponding Design Considerations for Report Rendering
article and Device Information Settings
Adding metadata describing the report's template is not supported, instead I can suggest you to send this information beside the exported report document.
Telerik UI for ASP.NET AJAX RadEditor control can be used to load the exported reports in browser - RadEditor: Import from DOCX and RTF
Please give it a try and let us know if you need any further help.
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