There is no one-click universal solution, but you have several reliable paths:
To let others download your file, go to Custom Settings > Advanced Mode > Download Settings and set it to "Show" . You must provide the URL of your original PDF for this button to work. Offline Viewing Options Download Pubhtml5 File
Downloading a PubHTML5 file is a straightforward process. Here are the steps: There is no one-click universal solution, but you