Your iPhone X/iPhone 8/ iPhone 8 Plus is unable to install new apps because for the app is stuck between different App installation stages like installing, Waiting and Loading. Here is the troubleshooting guide for use App on home screen after successfully install.
I found this tag at the bottom of app icon on iPhone’s main screen.
Fix: Apps Installing, Waiting and Loading on iPhone X/ iPhone 8/ iPhone 8 Plus
Not Enough Storage Space
App is offloaded
New Offload features came out this issues, Sometimes on download or install new iOS on iPhone; Apps automatically offload before to start the iOS download.
After installing the iOS update, you will get “Installing”, “Waiting”, or “Loading” on the app icon. Because during this app data is stored on your iPhone but not an app, it will download from app store automatically.
Hard Reset or Reboot
You have not a problem with enough space, Internet connection and more. The app is stuck on the home screen. You need to hard restart iPhone X/8/8 Plus.
Quickly Press and Release Volume up button
Now, Press and Release Volume down button
Last, Press and Hold Sleep/Wake button until you see the apple logo on the screen.
Start your iPhone, Press Side button again.
Check Internet connection
Slow internet connection gives message app Validation and Downloading in a process with “Waiting” tab.
Change internet connection or switch from cellular to WiFi or WiFi to Cellular.
Enjoy and fix Apps “Installing”, “Waiting”, or “Loading” on iPhone X, iPhone 8, 8 Plus after update iOS or Switch on New iPhone.