When designing for iPhone X, you must ensure that layouts fill the screen and aren't obscured by the device's rounded corners, sensor housing, or the indicator for accessing the Home screen. 

I would suggest you to use simulator (included with Xcode) to preview your app and check for clipping and other layout issues.

I have designed the app mockup on actual pixels so insert app designs and adjust inner shadows to make all the screens prominent.

Here you can get this Free iPhone X App Screen Mockup