before this you have get permission access from facebook by using below code :

try {
      const result = await LoginManager.logInWithPermissions([
        'user_photos',
        'user_videos',
      ]);

      if (result.isCancelled) {
        dispatch({ type: 'notGranted' });
        console.log('Permission request cancelled');
      } else {
        const data = await AccessToken.getCurrentAccessToken();
        console.log('Permission request granted', data);
        iscliked.current = true
        dispatch({ type: 'Granted' });
      }
    } catch (error) {
      dispatch({ type: 'notGranted' });
      console.error('Error requesting permissions:', error);
    }

after that you can share post publicly and all the world can see your post