After a helicopter has landed on a helipad, how do they get the helicopter into a hangar?

Some helicopters have wheels they are not visible when they are flying...like an aeroplane.

Skids are used mainly because they weigh less than wheels. On larger, more powerful helicopters, wheels are used because the utility and convenience can be more important than the savings in weight. In order to move a skid-equipped helicopter on the ground, one has to attach a set of ground-handling wheels, jack up the helicopter, and roll it (into the hangar for maintenance, for example).

The link in "If your helicopter already has the wheels as a permanent feature, it is more convenient to move around when the engine is shut down or the pilot has wandered off." shows skids with wheels.

https://www.helis.com/howflies/skids.php

Ideally, a helicopter won't be left on the landing pad if it's going into maintenance, and will be flown to the maintenance flight line. Once there, they get jockeyed around by one of these dollys, or the like.

http://www.freepatentsonline.com/4488612.html

I also know of times when it's more prudent to simply tow the aircraft on its skids, like when speed is more important than replacing a set of skids.