If your business is a sole proprietorship, partnership, corporation, or limited liability company (LLC) doing business under a name other than the real name of the person or entity then you are doing business under an "assumed name".
The Assumed Business Name Act (NCGS § 66-71.x) requires that businesses file assumed names with the Register of Deeds in any county in North Carolina where you will be doing business. The document that files or puts on record a business name of an individual, partnership or corporation other than its own name is referred to as Doing Business As (DBA) or Assumed Name.
See the complete Assumed Business Name Act here.
If you need more information on incorporation or initial filing of a limited partnership or LLC, please visit the Secretary of State's website.
If you do business in Wake County, you can fulfill all your Assumed Name filing requirements by registering with the Wake County Register of Deeds.
As of December 1, 2017, it is no longer necessary to register in each county in which you will do business.