For downloads, you have a custom field of the type Media Upload at your disposal. You can use this field to upload a new file or select an existing file from the media library.
The assigned file can then be displayed in the storefront as a download link.
Note: In some cases, special characters, spaces, or uppercase file extensions may cause issues. We therefore recommend using web-compatible file names (e.g. datasheet-red.pdf instead of Datasheet Red.PDF).
