What document is primarily used to prove ownership of a property?

The document primarily used to prove ownership of a property is a deed. A deed is a legal instrument that conveys title to real estate from one party to another, signifying the transfer of ownership. It contains essential information, such as the names of the buyer and seller, a description of the property, and is usually signed by the grantor (the seller) and notarized.

In contrast, lease agreements establish temporary rights to use a property rather than ownership. Title insurance protects against future claims against the title and confirms there are no existing claims or issues when the property is purchased, but it does not itself provide proof of ownership; it is a safeguard for the owner's title. A bill of sale relates specifically to personal property transactions, not real estate, which makes it irrelevant for proving ownership of real property. Therefore, the deed stands out as the definitive document establishing and proving ownership of a property.