Iphone 6 was very hot so I just use it as a hotspot to get on the Internet with my laptop he was really hot can't he broken by it?
First of all, please pay attention to your spelling in the future.
If a device gets temporarily hot, it's not bad, first it should become permanent, then you should think about it.
You should take better care there. In high heat, especially batteries can break. Better turn it off until it cools down again.