Hiking in any National Parks in Nepal needs passes with either individual or group trekkers while trekking. The hiking passes can buy at the check post-en-route and has to be shown to the following check posts or police on request until trekkers do not exit from the National Park boundary.
While the trekkers are heading to Everest Base Camp, they have to pay the local Govt. Tax along with Sagarmatha National Park hiking passes. It can also pay en-route.
While the trekkers are heading to the Annapurna region, they have to obtain hiking passes either in Kathmandu or Pokhara.