DocSend users have the ability to enable downloading and printing content anytime from the document viewer. This is controlled on a link-by-link basis and can be changed even after a link has been created and shared.
Users can update the option to allow downloading when accessing the link settings toggle ().
Note: There is not a way to make a document automatically download-only.
If you are viewing a document, and downloading has been enabled, you will see a "download" icon in the upper-right of the document viewer:
If downloading is not enabled for the link you're viewing, the "download" icon will be missing.