Your core business documents are those necessary documents outlining how a business will operate. Typically, these will include at minimum the formation document and the bylaws. These documents can also include internal policies and registering with various entities.
The formation document will vary depending on the type of business being created. A corporation will tend to require Articles of Incorporation and the issuance of stock. A limited liability corporation will need a membership agreement, while a partnership will have a partnership agreement. These formation documents then get filed with the appropriate state agency.
This formation document does two important things. First, the formation document sets out the type of entity being created. While that may not have a direct impact on how the business is run, it does have a large impact on how the entity is treated legally speaking. One example is taxation, with a partnership the taxes are passed through the entity to the owner(s). Corporations on the other hand are taxed as an entity and again at the individual level. Second, the formation document spells out a little of how the business is run. For example, a corporation will outline the number of stocks, the classification of stocks, voting strength of the stocks, among other concerns.
Bylaws, policies, and other registrations are all important as well but may not need to be filed. These documents either create the structure of how the business is run, such as with the bylaws and policies. Other documents protect the interests of the business, examples would be policies, registrations, and some provisions in the formation documents. Additional, some documents allow the business to act, specifically sales tax licenses.
Setting up a business can feel like a lot of work and to do it properly it may be. After all, none of these documents should be unchanged between businesses. The core business documents of a solely owned online store need to address concerns specific to the online world. On the other hand, a three person think tank will need very different documents. There may be a different entity between the two examples, which will mean different formation documents.
Good luck with your new business.