The Webflow CMS has a File type field that allows you to store files and make them available for download purposes.
In your Collection Page or Collection List you can then add a button or link, set it download and bind it to that CMS field.
However, there is no built-in means to get the original filename of that uploaded file, and display it.
For convenience, it's nice to have that option, so your link can read something like-
Without the need to manage that name in a separate plain text field.
Fortunately, when you upload a file to the CMS, Webflow prepends that name with an ID but otherwise preserves your original filename in the stored URL.