The corporate kit contains all these important documents that control the formation, organization, and management of your corporation—organized together in one place.
A corporate seal stamp is a round graphic that includes the corporation name, year of incorporation, and state of incorporation. Note that it's not something that is required, but some corporations like to have them. If you don't have one, it can be included in the Corporate Kit. The Corporate Seal Stamp can be found here (CORPORATE SEAL)