The BN is a numbering system that simplifies and streamlines the way businesses deal with the federal government. It is based on the idea of one business, one number.
Not all businesses require a BN and CRA program accounts so it is important to read Do you need a program account before registering.
The CRA is requesting that all new registrations provide the Name and the Social Insurance Number (SIN) of at least one owner/director of the business and the Major Business Activity (MBA) when registering.