If the business will operate as a sole proprietorship or a general partnership, an Assumed Name Certificate or d.b.a. (doing business as) for each name (or deviation of that name) the business will use must be on file with the county clerk in each county where a business premise will be maintained. If no business premise will be maintained, it should be filed in each county where business will be conducted.
If the business will operate as a corporation, limited partnership, or limited liability company, and the business will be identified by a name other than the name on file with the Secretary of State, an Assumed Name Certificate must be filed with the Secretary of State and each county in which the business will have a registered or principal office. Neither the filing of an Assumed Name Certificate nor the reservation or registration of a company name imparts any real protection to the party filing the certificate. It is merely a formal process that informs the general public of the registered agent for a business and where official contact with the business can be made.