The phrase "to require a clearance" means that permission or approval is needed before proceeding with or accessing something.
Sentences with «to require a clearance»
No final decisions have been made and any combination would require clearance from antitrust authorities and face potential opposition from unions, they said. (bloomberg.com)
The sliding doors require no clearance to open them and there's even a rail for hanging up your potential outfit for the day. (idealhome.co.uk)
Of course, some of the results might be proprietary and would require clearance from legal departments. (sciencemag.org)