My moto x4 phone is not turning on i drained to 0 and it won't turn on it has been charging for a few hours it is being recognized by my computer i have tried holding volume and power and nothing

Most probably it's on, the electronics all works, except for your screen. My assumption is that your screen needs to be replaced.

Explanation:

If you connected it to your PC and you can browse through your data it means the battery, processor and the memory is fine. The only thing is you don't see anything on your screen (it's black), which indicates that your output device was damaged and needs to be replaced.