The corporation’s Bylaws is the document that defines the organization’s operating standards.
Bylaws are considerably more detailed than Articles of Incorporation, and usually contain detailed information regarding the classes of stock, voting rights, participation in dividends, the election and responsibilities of directors and officers, rules and restrictions regarding the transfer of shares, indemnity provisions, rules for board meetings and shareholder meetings, and more.
In some states, you may file the Bylaws with the Secretary of State / Division of Corporations / whatever department deals with business filings and registrations; however, in most cases bylaws will only have to be maintained as an internal document. (That doesn’t mean you don’t need them, though. If you want to protect your personal assets from being seized to satisfy business debts and obligations, you must have bylaws – and you must ensure that your business actually does what those bylaws say.)