my iphone x turn into green screen then turn into black it did not open i try a hard reset but its not working

First try this. Work all through it.

If your iPhone, iPad, or iPod touch won't turn on or is frozen - Apple Support

There is no guarantee you can save any data since your last backup if you need to use the Restore option.

After that you should arrange a service or repair

https://support.apple.com/iphone/repair/service

Anything other than Screen or Battery may be a replacement phone and the price is in the article.