@MoiraskyeT surely you must know that you did not answer or even address @holly1's question.

The simple answer to the question is that Quickbooks Online removed the feature to see when a customer views an estimate or invoice with one of their brilliant Modern View "updates."

Only a couple years ago, Quickbooks online used to display a list of when an invoice or estimate was viewed at the bottom of the invoice or estimate itself. Now, Modern View hides this information behind a few clicks in the "Manage" tab, but it does not show WHO opened or viewed it. Quickbooks should know that users send their estimates and invoices to our customers' email, perhaps cc'ing several emails. All @holly1 is asking is for Quickbooks Online to display WHICH email opened the estimate so we can distinguish if the views were actually by our customers.