How many hours iphone x takes to cahrge fully

Obviously it depends on some conditions (i.e. battery status when you start charging it, ambient temperature, and so on), but generally speaking it could reach 100% in 2-3 hours.

Keep in mind that when it reaches 100%, your device will automatically stop charging.

Regards

Giulio

mind you, you should never run it to 0 before you charge it

read

Batteries - Maximizing Performance - Apple