Since you are in the meat bird forum I assume you are talking about butchering for meat and not a mercy killing to get it out of its misery. That narrows it down a little bit.
In general, the best way for you and the bird is how you can. What I mean by that is you do not want to flinch or close your eyes at a critical time, that might mean injury to you or the bird. You want it to be quick and sure. That method can be different for each of us.
I use the hatchet and stump method, but I grew up using an ax, hammer, and hatchet so I'm confident I can hit the target. I grew up butchering chickens that way, but it is hands on.
Many people use the cone method, especially people like you that haven't done it before. They may cut the arteries or use loppers, pipe cutters, or something else.
Some people like the broomstick method. You put the head on the ground and hold a broomstick or similar stick over the neck with your feet and jerk.
With any of these methods there are little tricks that make it go better. If you decide on a method come back on here so maybe someone can help you with details.
Another option is to find someone in your area that processed chickens, many do that. Or find a neighbor that can help you the first time or two. Having a knowledgeable person that can mentor you can make the process easier. I see you are in Pennsylvania, thanks for providing that information. If you haven't found this thread yet you might chat with your neighbors about this.
https://www.backyardchickens.com/threads/pennsylvania-unite.248345/page-7813