Indexing attachments and file resources
If you need to search and crawl files in WCM, it is mandatory to install and configure Document Conversion Services (DCS). This third party software included with HCL DX allows the DX Search Service to convert various types of document formats into a format which can be consumed and indexed by the search engine. Without DCS, attachments will not be not processed and, therefore, will not show up in search results.
For more information, see Document Conversion Services.