Allow/ Add download permissions to a customer's account

Many of my customers had purchased access to files prior to me using this plugin, but now the only way to give them access now is by emailing them a link. This was a jarring realization, and is tedious for me to now help my customers get their files. To keep everything running smoothly, I would like to be able to add download permissions/links to their account, similar to what I can do with files stored in the media library (See attached screenshot)