My iphone x can't open apps
It will start launching the application but will stop.
iPhone 7 Plus
Question marked as
Force a restart of your iPhone X, and see if things clear.
Hold the third button press of the restart until the Apple logo appears, past any sliders that might appear.
Force restart iPhone - Apple Support
If not… See if you can get a backup, and then perform a factory reset.
You’ll want to get a backup regardless, if you can.
How to factory reset your iPhone, iPad, or iPod touch - Apple Support (links to backup and restore)
If that fails, you’re headed for a discussion of your options and alternatives with Apple Support.