Files supports both quick and full preview of numerous file types. To support the preview function for files hosted on an on-premises server, you must install Preview Maker on the server.
Preview Maker is a set of ruby scripts with a small number of dependencies, You can run Preview Maker in any environment where a recent ruby, ffmpeg, and ascp are available. Attached to this article is the tarball containing the ruby scripts.
For more details and a procedure, see Installing the Files Preview Maker.