Policy document

You've just taken a flat on rent. At the time of finalising the agreement with the landlord, there is a document that is stamped and signed with all terms of the agreement - including rent, responsibilities, amenities included, etc.
This is exactly how an insurance document works. It is a legal contract with the insurance company that contains details about your coverage, premium payments, and the terms and conditions. In case the policyholder wants to verify certain details at any point, they can cross check with the policy document.