How can I determine if a client received and took possession of the Digital Delivery?

Tracking of Digital Deliveries is done from within the same tab they are sent. The recipients are displayed at the top along with the status (queued, sent, received, error). "Received" means the client has created their free account and taken possession. Hovering your mouse over the status of that recipient will show a timestamp of when that status changed. This can be used to determine when the client took possession and first viewed the project.