Ouch! Did you drop it or bang it? This looks like the screen is shot!
+
+
+
+
Here’s the needed part [https://www.ifixit.com/products/iphone-xs-max-screen https://www.ifixit.com/products/iphone-xs-max-screen] and the guide to install it [https://www.ifixit.com/Guide/iPhone+XS+Max+Screen+Replacement/113866]