iphone x not covering full screen

It's up the App Developers to update their apps to work on iPhone X. If Snapchat and Instagram haven't updated their apps to cover the entire screen there's nothing Apple can do. You can certainly reach out to the app developers and ask what if any future plans they have to better utilize the iPhone X screen.

check for app updates both the apps you listed have been updated for iphone x

alot of apps have not been and you will have the bars until they are

Double tap the screen in those apps to get it back to full screen.

I checked my Instragram app (I'm not on Snapchat) and it is full screen. If yours isn't, you can always delete the app, then re-download it and hopefully it will be right on your phone.

I am having this same problem I turned my phone off and back on but no updates is there any other solutions?