Exact Copy of One HDD to Another

[Sukkafish]

I'm trying to figure out how to go about completely copying/backing up my current HDD (OS plus everything else) onto another one that is freshly formatted that I will keep laying around if anything ever goes wrong with my PC. I've looked at the built in Backup tool in Win 10, but i'm not sure if it will do what exactly I want it to. And if that isn't possible, then what else could I do?

 

[Tanyac]

Macrium Reflect (Clone), Acronis True Image, CloneZilla... There are dozens of others.
https://www.google.com/search?q=hard+disk+cloning+softrware&ie=utf-8&oe=utf-8&client=firefox-b