iPhone X screen showing some hidden icon

Hello and welcome to Apple Support Communities, Fahad322.

If we understand your post correctly, your iPhone is performing slowing and you are seeing the image of an icon for an app. We’d like to help.

First, try restarting your iPhone:

Restart your iPhone

Does this icon appear at all times on your iPhone or does it appear only when viewing certain screens? Which iOS version are you using? Tap Settings > General > Software Update to find out. 

Thanks for using the Apple Support Communities.

Hello Fahad322.

At this point, we'd recommend contacting Apple Support directly. You can do that here:

Get Support

Cheers.