All sending, creations or deletions of quotes, contracts, questionnaires, and invoices can be seen in the "Activity" tab of your project.
You can also see activity for each individual document by clicking on the document you want to see the history for. This history will include when an item is opened/viewed.
The history will appear in the top right above the document.
KeyWordSearch: Activity, History, Views, Documents, Read Receipts, Confirmation