The Document access tracking package is used to register in the document's history the fact that users have accessed the document, and so have probably read it.
It adds actions done by the server. You do not have any action to do so the access to documents is logged. Just like there is a new line in the event log every time the document is modified, there will be a line added when users click on the document to consult it.
In this History tab, when a user clicks on the document, a new event is registered, called "Access". It is indicated the user who opened the document and the date and time at which he/she accessed it.