The phrase "to need a permit" means that you are required to get official permission or approval from someone in authority in order to do something specific. Full definition
Significant out buildings or other residential structures may need a permit for removal. (remonline.com)
On Kings day you don't need the permit to sell your items on the street. (nofearoffashion.com)
If your business location will be accessible to the public, or if it deals with any sort of hazardous materials, you'll likely need a permit from your local fire department. (rocketlawyer.com)