The My Cloud Home (MCH) is geared towards the Home user and some office file support can be lacking, however the preview function is readily available with the desktop WD Discovery integration with the MCH.
With the web app, the MCH provides the same functionality as a competing product such as the Synology where you don’t even see a PDF preview:
Those who wish to only use the Web app will have to look at other cloud storage solution or at least pay more attention to the appropriate subforum to let their voices heard. Judging by the lack of posts, there hasn’t been much demand for the functionality since 2018:
