Broadly speaking, the owner is the individual or group who controls or owns a football team or organization. The owner(s) are the highest ranking individuals in the organization and dictate what happens below them. Most owners will have other high-ranking jobs to make them their money, so their ownership of the team is normally a part-time job. Generally, owners will hire a team president to handle day-to-day operations, but the team president must answer to the owner and get approval on important decisions such as budgeting, big trades, or draft picks. The NFL has 32 teams with separate ownership; most owners have full ownership of their respective franchises, however some teams have multiple partial owners.
NFL owners have other responsibilities outside of delegating who manages their teams. Owners frequently meet and hold votes to make decisions on league issues and rule changes. Even more importantly, the owners are most frequently the face of their franchise, and help create and promote the culture all the way throughout the organization.
Below is a full list of NFL teams and their respective owners.